1
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Langdon QK, Groh JS, Aguillon SM, Powell DL, Gunn T, Payne C, Baczenas JJ, Donny A, Dodge TO, Du K, Schartl M, Ríos-Cárdenas O, Gutiérrez-Rodríguez C, Morris M, Schumer M. Swordtail fish hybrids reveal that genome evolution is surprisingly predictable after initial hybridization. PLoS Biol 2024; 22:e3002742. [PMID: 39186811 PMCID: PMC11379403 DOI: 10.1371/journal.pbio.3002742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Revised: 09/06/2024] [Accepted: 07/09/2024] [Indexed: 08/28/2024] Open
Abstract
Over the past 2 decades, biologists have come to appreciate that hybridization, or genetic exchange between distinct lineages, is remarkably common-not just in particular lineages but in taxonomic groups across the tree of life. As a result, the genomes of many modern species harbor regions inherited from related species. This observation has raised fundamental questions about the degree to which the genomic outcomes of hybridization are repeatable and the degree to which natural selection drives such repeatability. However, a lack of appropriate systems to answer these questions has limited empirical progress in this area. Here, we leverage independently formed hybrid populations between the swordtail fish Xiphophorus birchmanni and X. cortezi to address this fundamental question. We find that local ancestry in one hybrid population is remarkably predictive of local ancestry in another, demographically independent hybrid population. Applying newly developed methods, we can attribute much of this repeatability to strong selection in the earliest generations after initial hybridization. We complement these analyses with time-series data that demonstrates that ancestry at regions under selection has remained stable over the past approximately 40 generations of evolution. Finally, we compare our results to the well-studied X. birchmanni × X. malinche hybrid populations and conclude that deeper evolutionary divergence has resulted in stronger selection and higher repeatability in patterns of local ancestry in hybrids between X. birchmanni and X. cortezi.
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Affiliation(s)
- Quinn K Langdon
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
| | - Jeffrey S Groh
- Center for Population Biology and Department of Evolution and Ecology, University of California, Davis, Davis, California, United States of America
| | - Stepfanie M Aguillon
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, United States of America
| | - Daniel L Powell
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Theresa Gunn
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
| | - Cheyenne Payne
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
| | - John J Baczenas
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Alex Donny
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
| | - Tristram O Dodge
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
| | - Kang Du
- Xiphophorus Genetic Stock Center, Texas State University San Marcos, San Marcos, United States of America
| | - Manfred Schartl
- Xiphophorus Genetic Stock Center, Texas State University San Marcos, San Marcos, United States of America
- Developmental Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Oscar Ríos-Cárdenas
- Red de Biología Evolutiva, Instituto de Ecología, A.C., Xalapa, Veracruz, Mexico
| | | | - Molly Morris
- Department of Biological Sciences, Ohio University, Athens, Ohio, United States of America
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas "Aguazarca", A.C., Calnali, Hidalgo, Mexico
- Freeman Hrabowski Fellow, Howard Hughes Medical Institute, Stanford, California, United States of America
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2
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Pfennig A, Lachance J. The evolutionary fate of Neanderthal DNA in 30,780 admixed genomes with recent African-like ancestry. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.25.605203. [PMID: 39091830 PMCID: PMC11291122 DOI: 10.1101/2024.07.25.605203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 08/04/2024]
Abstract
Following introgression, Neanderthal DNA was initially purged from non-African genomes, but the evolutionary fate of remaining introgressed DNA has not been explored yet. To fill this gap, we analyzed 30,780 admixed genomes with African-like ancestry from the All of Us research program, in which Neanderthal alleles encountered novel genetic backgrounds during the last 15 generations. Observed amounts of Neanderthal DNA approximately match expectations based on ancestry proportions, suggesting neutral evolution. Nevertheless, we identified genomic regions that have significantly less or more Neanderthal ancestry than expected and are associated with spermatogenesis, innate immunity, and other biological processes. We also identified three novel introgression desert-like regions in recently admixed genomes, whose genetic features are compatible with hybrid incompatibilities and intrinsic negative selection. Overall, we find that much of the remaining Neanderthal DNA in human genomes is not under strong selection, and complex evolutionary dynamics have shaped introgression landscapes in our species.
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Affiliation(s)
- Aaron Pfennig
- School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr, Atlanta, 30332, GA, USA
| | - Joseph Lachance
- School of Biological Sciences, Georgia Institute of Technology, 950 Atlantic Dr, Atlanta, 30332, GA, USA
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3
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Li L, Comi TJ, Bierman RF, Akey JM. Recurrent gene flow between Neanderthals and modern humans over the past 200,000 years. Science 2024; 385:eadi1768. [PMID: 38991054 DOI: 10.1126/science.adi1768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 05/14/2024] [Indexed: 07/13/2024]
Abstract
Although it is well known that the ancestors of modern humans and Neanderthals admixed, the effects of gene flow on the Neanderthal genome are not well understood. We develop methods to estimate the amount of human-introgressed sequences in Neanderthals and apply it to whole-genome sequence data from 2000 modern humans and three Neanderthals. We estimate that Neanderthals have 2.5 to 3.7% human ancestry, and we leverage human-introgressed sequences in Neanderthals to revise estimates of Neanderthal ancestry in modern humans, show that Neanderthal population sizes were significantly smaller than previously estimated, and identify two distinct waves of modern human gene flow into Neanderthals. Our data provide insights into the genetic legacy of recurrent gene flow between modern humans and Neanderthals.
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Affiliation(s)
- Liming Li
- Department of Medical Genetics and Developmental Biology, School of Medicine, The Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, Southeast University, Nanjing 210009, China
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Troy J Comi
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Rob F Bierman
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
| | - Joshua M Akey
- The Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08540, USA
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4
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Aneli S, Ceccatelli Berti C, Gilea AI, Birolo G, Mutti G, Pavesi A, Baruffini E, Goffrini P, Capelli C. Functional characterization of archaic-specific variants in mitonuclear genes: insights from comparative analysis in S. cerevisiae. Hum Mol Genet 2024; 33:1152-1163. [PMID: 38558123 DOI: 10.1093/hmg/ddae057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 02/29/2024] [Accepted: 03/14/2024] [Indexed: 04/04/2024] Open
Abstract
Neanderthal and Denisovan hybridisation with modern humans has generated a non-random genomic distribution of introgressed regions, the result of drift and selection dynamics. Cross-species genomic incompatibility and more efficient removal of slightly deleterious archaic variants have been proposed as selection-based processes involved in the post-hybridisation purge of archaic introgressed regions. Both scenarios require the presence of functionally different alleles across Homo species onto which selection operated differently according to which populations hosted them, but only a few of these variants have been pinpointed so far. In order to identify functionally divergent archaic variants removed in humans, we focused on mitonuclear genes, which are underrepresented in the genomic landscape of archaic humans. We searched for non-synonymous, fixed, archaic-derived variants present in mitonuclear genes, rare or absent in human populations. We then compared the functional impact of archaic and human variants in the model organism Saccharomyces cerevisiae. Notably, a variant within the mitochondrial tyrosyl-tRNA synthetase 2 (YARS2) gene exhibited a significant decrease in respiratory activity and a substantial reduction of Cox2 levels, a proxy for mitochondrial protein biosynthesis, coupled with the accumulation of the YARS2 protein precursor and a lower amount of mature enzyme. Our work suggests that this variant is associated with mitochondrial functionality impairment, thus contributing to the purging of archaic introgression in YARS2. While different molecular mechanisms may have impacted other mitonuclear genes, our approach can be extended to the functional screening of mitonuclear genetic variants present across species and populations.
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Affiliation(s)
- Serena Aneli
- Department of Public Health Sciences and Pediatrics, University of Turin, C.so Galileo Galilei 22, Turin 10126, Italy
| | - Camilla Ceccatelli Berti
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/a, Parma 43124, Italy
| | - Alexandru Ionut Gilea
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/a, Parma 43124, Italy
| | - Giovanni Birolo
- Department of Medical Sciences, University of Turin, Via Santena 5, Turin 10126, Italy
| | - Giacomo Mutti
- Barcelona Supercomputing Centre (BSC-CNS), Department of Life Sciences, Plaça Eusebi Güell, 1-3, Barcelona 08034, Spain
- Institute for Research in Biomedicine (IRB Barcelona), Department of Mechanisms of Disease, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Angelo Pavesi
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/a, Parma 43124, Italy
| | - Enrico Baruffini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/a, Parma 43124, Italy
| | - Paola Goffrini
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/a, Parma 43124, Italy
| | - Cristian Capelli
- Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parco Area delle Scienze 11/a, Parma 43124, Italy
- Department of Biology, University of Oxford, 11a Mansfield Rd, Oxford OX1 3SZ, United Kingdom
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5
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Glasenapp MR, Pogson GH. Selection Shapes the Genomic Landscape of Introgressed Ancestry in a Pair of Sympatric Sea Urchin Species. Genome Biol Evol 2024; 16:evae124. [PMID: 38874390 PMCID: PMC11212366 DOI: 10.1093/gbe/evae124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 05/10/2024] [Accepted: 06/07/2024] [Indexed: 06/15/2024] Open
Abstract
A growing number of recent studies have demonstrated that introgression is common across the tree of life. However, we still have a limited understanding of the fate and fitness consequence of introgressed variation at the whole-genome scale across diverse taxonomic groups. Here, we implemented a phylogenetic hidden Markov model to identify and characterize introgressed genomic regions in a pair of well-diverged, nonsister sea urchin species: Strongylocentrotus pallidus and Strongylocentrotus droebachiensis. Despite the old age of introgression, a sizable fraction of the genome (1% to 5%) exhibited introgressed ancestry, including numerous genes showing signals of historical positive selection that may represent cases of adaptive introgression. One striking result was the overrepresentation of hyalin genes in the identified introgressed regions despite observing considerable overall evidence of selection against introgression. There was a negative correlation between introgression and chromosome gene density, and two chromosomes were observed with considerably reduced introgression. Relative to the nonintrogressed genome-wide background, introgressed regions had significantly reduced nucleotide divergence (dXY) and overlapped fewer protein-coding genes, coding bases, and genes with a history of positive selection. Additionally, genes residing within introgressed regions showed slower rates of evolution (dN, dS, dN/dS) than random samples of genes without introgressed ancestry. Overall, our findings are consistent with widespread selection against introgressed ancestry across the genome and suggest that slowly evolving, low-divergence genomic regions are more likely to move between species and avoid negative selection following hybridization and introgression.
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Affiliation(s)
- Matthew R Glasenapp
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, USA
| | - Grant H Pogson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, USA
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6
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Pauly R, Johnson L, Feltus FA, Casanova EL. Enrichment of a subset of Neanderthal polymorphisms in autistic probands and siblings. Mol Psychiatry 2024:10.1038/s41380-024-02593-7. [PMID: 38760502 DOI: 10.1038/s41380-024-02593-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 05/01/2024] [Accepted: 05/02/2024] [Indexed: 05/19/2024]
Abstract
Homo sapiens and Neanderthals underwent hybridization during the Middle/Upper Paleolithic age, culminating in retention of small amounts of Neanderthal-derived DNA in the modern human genome. In the current study, we address the potential roles Neanderthal single nucleotide polymorphisms (SNP) may be playing in autism susceptibility in samples of black non-Hispanic, white Hispanic, and white non-Hispanic people using data from the Simons Foundation Powering Autism Research (SPARK), Genotype-Tissue Expression (GTEx), and 1000 Genomes (1000G) databases. We have discovered that rare variants are significantly enriched in autistic probands compared to race-matched controls. In addition, we have identified 25 rare and common SNPs that are significantly enriched in autism on different ethnic backgrounds, some of which show significant clinical associations. We have also identified other SNPs that share more specific genotype-phenotype correlations but which are not necessarily enriched in autism and yet may nevertheless play roles in comorbid phenotype expression (e.g., intellectual disability, epilepsy, and language regression). These results strongly suggest Neanderthal-derived DNA is playing a significant role in autism susceptibility across major populations in the United States.
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Affiliation(s)
- Rini Pauly
- Biomedical Data Science and Informatics Program, Clemson University, Clemson, SC, 29634, USA
| | - Layla Johnson
- Department of Psychology, Loyola University, New Orleans, New Orleans, LA, 70118, USA
| | - F Alex Feltus
- Biomedical Data Science and Informatics Program, Clemson University, Clemson, SC, 29634, USA
- Department of Genetics and Biochemistry, Clemson University, Clemson, SC, 29634, USA
- Center for Human Genetics, Clemson University, Clemson, SC, 29634, USA
| | - Emily L Casanova
- Department of Psychology, Loyola University, New Orleans, New Orleans, LA, 70118, USA.
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7
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Iasi LNM, Chintalapati M, Skov L, Mesa AB, Hajdinjak M, Peter BM, Moorjani P. Neandertal ancestry through time: Insights from genomes of ancient and present-day humans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.13.593955. [PMID: 38798350 PMCID: PMC11118355 DOI: 10.1101/2024.05.13.593955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Gene flow from Neandertals has shaped the landscape of genetic and phenotypic variation in modern humans. We identify the location and size of introgressed Neandertal ancestry segments in more than 300 genomes spanning the last 50,000 years. We study how Neandertal ancestry is shared among individuals to infer the time and duration of the Neandertal gene flow. We find the correlation of Neandertal segment locations across individuals and their divergence to sequenced Neandertals, both support a model of single major Neandertal gene flow. Our catalog of introgressed segments through time confirms that most natural selection-positive and negative-on Neandertal ancestry variants occurred immediately after the gene flow, and provides new insights into how the contact with Neandertals shaped human origins and adaptation.
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Affiliation(s)
- Leonardo N. M. Iasi
- Department for Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology; Leipzig, 04301, Germany
| | - Manjusha Chintalapati
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley, CA 94720, USA
| | - Laurits Skov
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley, CA 94720, USA
| | - Alba Bossoms Mesa
- Department for Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology; Leipzig, 04301, Germany
| | - Mateja Hajdinjak
- Department for Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology; Leipzig, 04301, Germany
- The Francis Crick Institute; London, NW1 1AT, UK
| | - Benjamin M. Peter
- Department for Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology; Leipzig, 04301, Germany
- Department of Biology, University of Rochester; Rochester NY, 14620,USA
| | - Priya Moorjani
- Department of Molecular and Cell Biology, University of California Berkeley; Berkeley, CA 94720, USA
- Center for Computational Biology, University of California Berkeley; Berkeley, CA 94720, USA
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8
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Groh JS, Coop G. The temporal and genomic scale of selection following hybridization. Proc Natl Acad Sci U S A 2024; 121:e2309168121. [PMID: 38489387 PMCID: PMC10962946 DOI: 10.1073/pnas.2309168121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 01/30/2024] [Indexed: 03/17/2024] Open
Abstract
Genomic evidence supports an important role for selection in shaping patterns of introgression along the genome, but frameworks for understanding the evolutionary dynamics within hybrid populations that underlie these patterns have been lacking. Due to the clock-like effect of recombination in hybrids breaking up parental haplotypes, drift and selection produce predictable patterns of ancestry variation at varying spatial genomic scales through time. Here, we develop methods based on the Discrete Wavelet Transform to study the genomic scale of local ancestry variation and its association with recombination rates and show that these methods capture temporal dynamics of drift and genome-wide selection after hybridization. We apply these methods to published datasets from hybrid populations of swordtail fish (Xiphophorus) and baboons (Papio) and to inferred Neanderthal introgression in modern humans. Across systems, upward of 20% of variation in local ancestry at the broadest genomic scales can be attributed to systematic selection against introgressed alleles, consistent with strong selection acting on early-generation hybrids. Signatures of selection at fine genomic scales suggest selection over longer time scales; however, we suggest that our ability to confidently infer selection at fine scales is likely limited by inherent biases in current methods for estimating local ancestry from contiguous segments of genomic similarity. Wavelet approaches will become widely applicable as genomic data from systems with introgression become increasingly available and can help shed light on generalities of the genomic consequences of interspecific hybridization.
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Affiliation(s)
- Jeffrey S. Groh
- Department of Evolution and Ecology and Center for Population Biology, University of California, Davis, CA95616
| | - Graham Coop
- Department of Evolution and Ecology and Center for Population Biology, University of California, Davis, CA95616
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9
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Feng X, Merilä J, Löytynoja A. Secondary Contact, Introgressive Hybridization, and Genome Stabilization in Sticklebacks. Mol Biol Evol 2024; 41:msae031. [PMID: 38366566 PMCID: PMC10903534 DOI: 10.1093/molbev/msae031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 12/20/2023] [Accepted: 02/09/2024] [Indexed: 02/18/2024] Open
Abstract
Advances in genomic studies have revealed that hybridization in nature is pervasive and raised questions about the dynamics of different genetic and evolutionary factors following the initial hybridization event. While recent research has proposed that the genomic outcomes of hybridization might be predictable to some extent, many uncertainties remain. With comprehensive whole-genome sequence data, we investigated the genetic introgression between 2 divergent lineages of 9-spined sticklebacks (Pungitius pungitius) in the Baltic Sea. We found that the intensity and direction of selection on the introgressed variation has varied across different genomic elements: while functionally important regions displayed reduced rates of introgression, promoter regions showed enrichment. Despite the general trend of negative selection, we identified specific genomic regions that were enriched for introgressed variants, and within these regions, we detected footprints of selection, indicating adaptive introgression. Geographically, we found the selection against the functional changes to be strongest in the vicinity of the secondary contact zone and weaken as a function of distance from the initial contact. Altogether, the results suggest that the stabilization of introgressed variation in the genomes is a complex, multistage process involving both negative and positive selection. In spite of the predominance of negative selection against introgressed variants, we also found evidence for adaptive introgression variants likely associated with adaptation to Baltic Sea environmental conditions.
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Affiliation(s)
- Xueyun Feng
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
| | - Juha Merilä
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki 00014, Finland
- Area of Ecology and Biodiversity, The School of Biological Sciences, Kadoorie Biological Sciences Building, The University of Hong Kong, Hong Kong, Hong Kong SAR
| | - Ari Löytynoja
- Institute of Biotechnology, University of Helsinki, Helsinki 00014, Finland
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10
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Peyrégne S, Slon V, Kelso J. More than a decade of genetic research on the Denisovans. Nat Rev Genet 2024; 25:83-103. [PMID: 37723347 DOI: 10.1038/s41576-023-00643-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2023] [Indexed: 09/20/2023]
Abstract
Denisovans, a group of now extinct humans who lived in Eastern Eurasia in the Middle and Late Pleistocene, were first identified from DNA sequences just over a decade ago. Only ten fragmentary remains from two sites have been attributed to Denisovans based entirely on molecular information. Nevertheless, there has been great interest in using genetic data to understand Denisovans and their place in human history. From the reconstruction of a single high-quality genome, it has been possible to infer their population history, including events of admixture with other human groups. Additionally, the identification of Denisovan DNA in the genomes of present-day individuals has provided insights into the timing and routes of dispersal of ancient modern humans into Asia and Oceania, as well as the contributions of archaic DNA to the physiology of present-day people. In this Review, we synthesize more than a decade of research on Denisovans, reconcile controversies and summarize insights into their population history and phenotype. We also highlight how our growing knowledge about Denisovans has provided insights into our own evolutionary history.
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Affiliation(s)
- Stéphane Peyrégne
- Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany.
| | - Viviane Slon
- Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany
- Department of Anatomy and Anthropology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- The Dan David Center for Human Evolution and Biohistory Research, Tel Aviv University, Tel Aviv, Israel
| | - Janet Kelso
- Department of Evolutionary Genetics, Max-Planck-Institute for Evolutionary Anthropology, Leipzig, Germany.
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11
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Langdon QK, Groh JS, Aguillon SM, Powell DL, Gunn T, Payne C, Baczenas JJ, Donny A, Dodge TO, Du K, Schartl M, Ríos-Cárdenas O, Gutierrez-Rodríguez C, Morris M, Schumer M. Genome evolution is surprisingly predictable after initial hybridization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.21.572897. [PMID: 38187753 PMCID: PMC10769416 DOI: 10.1101/2023.12.21.572897] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Over the past two decades, evolutionary biologists have come to appreciate that hybridization, or genetic exchange between distinct lineages, is remarkably common - not just in particular lineages but in taxonomic groups across the tree of life. As a result, the genomes of many modern species harbor regions inherited from related species. This observation has raised fundamental questions about the degree to which the genomic outcomes of hybridization are repeatable and the degree to which natural selection drives such repeatability. However, a lack of appropriate systems to answer these questions has limited empirical progress in this area. Here, we leverage independently formed hybrid populations between the swordtail fish Xiphophorus birchmanni and X. cortezi to address this fundamental question. We find that local ancestry in one hybrid population is remarkably predictive of local ancestry in another, demographically independent hybrid population. Applying newly developed methods, we can attribute much of this repeatability to strong selection in the earliest generations after initial hybridization. We complement these analyses with time-series data that demonstrates that ancestry at regions under selection has remained stable over the past ~40 generations of evolution. Finally, we compare our results to the well-studied X. birchmanni×X. malinche hybrid populations and conclude that deeper evolutionary divergence has resulted in stronger selection and higher repeatability in patterns of local ancestry in hybrids between X. birchmanni and X. cortezi.
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Affiliation(s)
- Quinn K. Langdon
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
- Gladstone Institute of Virology, Gladstone Institutes, San Francisco, California
| | - Jeffrey S. Groh
- Center for Population Biology and Department of Evolution and Ecology, University of California, Davis
| | - Stepfanie M. Aguillon
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles
| | - Daniel L. Powell
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Theresa Gunn
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Cheyenne Payne
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | | | - Alex Donny
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Tristram O. Dodge
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
| | - Kang Du
- Xiphophorus Genetic Stock Center, Texas State University San Marcos
| | - Manfred Schartl
- Xiphophorus Genetic Stock Center, Texas State University San Marcos
- Developmental Biochemistry, Biocenter, University of Würzburg
| | | | | | | | - Molly Schumer
- Department of Biology, Stanford University
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C
- Freeman Hrabowski Fellow, Howard Hughes Medical Institute
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12
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Di Santo LN, Quilodrán CS, Currat M. Temporal Variation in Introgressed Segments' Length Statistics Computed from a Limited Number of Ancient Genomes Sheds Light on Past Admixture Pulses. Mol Biol Evol 2023; 40:msad252. [PMID: 37992125 PMCID: PMC10715198 DOI: 10.1093/molbev/msad252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 10/16/2023] [Accepted: 11/09/2023] [Indexed: 11/24/2023] Open
Abstract
Hybridization is recognized as an important evolutionary force, but identifying and timing admixture events between divergent lineages remain a major aim of evolutionary biology. While this has traditionally been done using inferential tools on contemporary genomes, the latest advances in paleogenomics have provided a growing wealth of temporally distributed genomic data. Here, we used individual-based simulations to generate chromosome-level genomic data for a 2-population system and described temporal neutral introgression patterns under a single- and 2-pulse admixture model. We computed 6 summary statistics aiming to inform the timing and number of admixture pulses between interbreeding entities: lengths of introgressed sequences and their variance within genomes, as well as genome-wide introgression proportions and related measures. The first 2 statistics could confidently be used to infer interlineage hybridization history, peaking at the beginning and shortly after an admixture pulse. Temporal variation in introgression proportions and related statistics provided more limited insights, particularly when considering their application to ancient genomes still scant in number. Lastly, we computed these statistics on Homo sapiens paleogenomes and successfully inferred the hybridization pulse from Neanderthal that occurred approximately 40 to 60 kya. The scarce number of genomes dating from this period prevented more precise inferences, but the accumulation of paleogenomic data opens promising perspectives as our approach only requires a limited number of ancient genomes.
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Affiliation(s)
- Lionel N Di Santo
- Department of Genetics and Evolution, University of Geneva, Geneva CH-1205
| | | | - Mathias Currat
- Department of Genetics and Evolution, University of Geneva, Geneva CH-1205
- Institute of Genetics and Genomics in Geneva (IGE3), University of Geneva, Geneva CH-1205
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13
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Wroblewski TH, Witt KE, Lee SB, Malhi RS, Peede D, Huerta-Sánchez E, Villanea FA, Claw KG. Pharmacogenetic Variation in Neanderthals and Denisovans and Implications for Human Health and Response to Medications. Genome Biol Evol 2023; 15:evad222. [PMID: 38051947 PMCID: PMC10727477 DOI: 10.1093/gbe/evad222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 11/08/2023] [Accepted: 11/16/2023] [Indexed: 12/07/2023] Open
Abstract
Modern humans carry both Neanderthal and Denisovan (archaic) genome elements that are part of the human gene pool and affect the life and health of living individuals. The impact of archaic DNA may be particularly evident in pharmacogenes-genes responsible for the processing of exogenous substances such as food, pollutants, and medications-as these can relate to changing environmental effects, and beneficial variants may have been retained as modern humans encountered new environments. However, the health implications and contribution of archaic ancestry in pharmacogenes of modern humans remain understudied. Here, we explore 11 key cytochrome P450 genes (CYP450) involved in 75% of all drug metabolizing reactions in three Neanderthal and one Denisovan individuals and examine archaic introgression in modern human populations. We infer the metabolizing efficiency of these 11 CYP450 genes in archaic individuals and find important predicted phenotypic differences relative to modern human variants. We identify several single nucleotide variants shared between archaic and modern humans in each gene, including some potentially function-altering mutations in archaic CYP450 genes, which may result in altered metabolism in living people carrying these variants. We also identified several variants in the archaic CYP450 genes that are novel and unique to archaic humans as well as one gene, CYP2B6, that shows evidence for a gene duplication found only in Neanderthals and modern Africans. Finally, we highlight CYP2A6, CYP2C9, and CYP2J2, genes which show evidence for archaic introgression into modern humans and posit evolutionary hypotheses that explain their allele frequencies in modern populations.
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Affiliation(s)
- Tadeusz H Wroblewski
- Department of Biomedical Informatics, Colorado Center for Personalized Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kelsey E Witt
- Center for Human Genetics and Department of Genetics and Biochemistry, Clemson University, South Carolina, USA
| | - Seung-been Lee
- Precision Medicine Institute, Macrogen Inc., Seoul, Republic of Korea
| | - Ripan S Malhi
- Department of Anthropology and Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Illinois, USA
| | - David Peede
- Department of Ecology, Evolution, and Organismal Biology and Center for Computational and Molecular Biology, Brown University, Providence, Rhode Island, USA
- Institute at Brown for Environment and Society, Brown University, Providence, Rhode Island, USA
| | - Emilia Huerta-Sánchez
- Department of Ecology, Evolution, and Organismal Biology and Center for Computational and Molecular Biology, Brown University, Providence, Rhode Island, USA
| | | | - Katrina G Claw
- Department of Biomedical Informatics, Colorado Center for Personalized Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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14
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Urnikyte A, Masiulyte A, Pranckeniene L, Kučinskas V. Disentangling archaic introgression and genomic signatures of selection at human immunity genes. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2023; 116:105528. [PMID: 37977419 DOI: 10.1016/j.meegid.2023.105528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 11/04/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Pathogens and infectious diseases have imposed exceptionally strong selective pressure on ancient and modern human genomes and contributed to the current variation in many genes. There is evidence that modern humans acquired immune variants through interbreeding with ancient hominins, but the impact of such variants on human traits is not fully understood. The main objectives of this research were to infer the genetic signatures of positive selection that may be involved in adaptation to infectious diseases and to investigate the function of Neanderthal alleles identified within a set of 50 Lithuanian genomes. Introgressed regions were identified using the machine learning tool ArchIE. Recent positive selection signatures were analysed using iHS. We detected high-scoring signals of positive selection at innate immunity genes (EMB, PARP8, HLAC, and CDSN) and evaluated their interactions with the structural proteins of pathogens. Interactions with human immunodeficiency virus (HIV) 1 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were identified. Overall, genomic regions introgressed from Neanderthals were shown to be enriched in genes related to immunity, keratinocyte differentiation, and sensory perception.
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Affiliation(s)
- Alina Urnikyte
- Faculty of Medicine, Department of Human and Medical Genetics, Institute of Biomedical Sciences, Vilnius University, Santariskiu Street 2, Vilnius LT-08661, Lithuania.
| | - Abigaile Masiulyte
- Faculty of Medicine, Department of Human and Medical Genetics, Institute of Biomedical Sciences, Vilnius University, Santariskiu Street 2, Vilnius LT-08661, Lithuania
| | - Laura Pranckeniene
- Faculty of Medicine, Department of Human and Medical Genetics, Institute of Biomedical Sciences, Vilnius University, Santariskiu Street 2, Vilnius LT-08661, Lithuania.
| | - Vaidutis Kučinskas
- Faculty of Medicine, Department of Human and Medical Genetics, Institute of Biomedical Sciences, Vilnius University, Santariskiu Street 2, Vilnius LT-08661, Lithuania.
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15
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Ragsdale AP. Human evolution: Neanderthal footprints in African genomes. Curr Biol 2023; 33:R1197-R1200. [PMID: 37989099 DOI: 10.1016/j.cub.2023.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023]
Abstract
Human and Neanderthal populations met and mixed on multiple occasions over evolutionary time, resulting in the exchange of genetic material. New genomic analyses of diverse African populations reveal a history of bidirectional gene flow and selection acting on introgressed alleles.
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Affiliation(s)
- Aaron P Ragsdale
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA.
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16
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Quilodrán CS, Rio J, Tsoupas A, Currat M. Past human expansions shaped the spatial pattern of Neanderthal ancestry. SCIENCE ADVANCES 2023; 9:eadg9817. [PMID: 37851812 PMCID: PMC10584333 DOI: 10.1126/sciadv.adg9817] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/11/2023] [Indexed: 10/20/2023]
Abstract
The worldwide expansion of modern humans (Homo sapiens) started before the extinction of Neanderthals (Homo neanderthalensis). Both species coexisted and interbred, leading to slightly higher introgression in East Asians than in Europeans. This distinct ancestry level has been argued to result from selection, but range expansions of modern humans could provide an alternative explanation. This hypothesis would lead to spatial introgression gradients, increasing with distance from the expansion source. We investigate the presence of Neanderthal introgression gradients after past human expansions by analyzing Eurasian paleogenomes. We show that the out-of-Africa expansion resulted in spatial gradients of Neanderthal ancestry that persisted through time. While keeping the same gradient orientation, the expansion of early Neolithic farmers contributed decisively to reducing the Neanderthal introgression in European populations compared to Asian populations. This is because Neolithic farmers carried less Neanderthal DNA than preceding Paleolithic hunter-gatherers. This study shows that inferences about past human population dynamics can be made from the spatiotemporal variation in archaic introgression.
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Affiliation(s)
| | - Jérémy Rio
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Alexandros Tsoupas
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Mathias Currat
- Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
- Institute of Genetics and Genomics in Geneva (IGE3), University of Geneva, Geneva, Switzerland
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17
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Chevy ET, Huerta-Sánchez E, Ramachandran S. Integrating sex-bias into studies of archaic introgression on chromosome X. PLoS Genet 2023; 19:e1010399. [PMID: 37578977 PMCID: PMC10449224 DOI: 10.1371/journal.pgen.1010399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 08/24/2023] [Accepted: 07/10/2023] [Indexed: 08/16/2023] Open
Abstract
Evidence of interbreeding between archaic hominins and humans comes from methods that infer the locations of segments of archaic haplotypes, or 'archaic coverage' using the genomes of people living today. As more estimates of archaic coverage have emerged, it has become clear that most of this coverage is found on the autosomes- very little is retained on chromosome X. Here, we summarize published estimates of archaic coverage on autosomes and chromosome X from extant human samples. We find on average 7 times more archaic coverage on autosomes than chromosome X, and identify broad continental patterns in this ratio: greatest in European samples, and least in South Asian samples. We also perform extensive simulation studies to investigate how the amount of archaic coverage, lengths of coverage, and rates of purging of archaic coverage are affected by sex-bias caused by an unequal sex ratio within the archaic introgressors. Our results generally confirm that, with increasing male sex-bias, less archaic coverage is retained on chromosome X. Ours is the first study to explicitly model such sex-bias and its potential role in creating the dearth of archaic coverage on chromosome X.
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Affiliation(s)
- Elizabeth T. Chevy
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, United States of America
| | - Emilia Huerta-Sánchez
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, United States of America
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, United States of America
| | - Sohini Ramachandran
- Center for Computational Molecular Biology, Brown University, Providence, Rhode Island, United States of America
- Department of Ecology, Evolution, and Organismal Biology, Brown University, Providence, Rhode Island, United States of America
- Data Science Initiative, Brown University, Providence, Rhode Island, United States of America
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18
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Wong ELY, Filatov DA. The role of recombination landscape in species hybridisation and speciation. FRONTIERS IN PLANT SCIENCE 2023; 14:1223148. [PMID: 37484464 PMCID: PMC10361763 DOI: 10.3389/fpls.2023.1223148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/13/2023] [Indexed: 07/25/2023]
Abstract
It is now well recognised that closely related species can hybridize and exchange genetic material, which may promote or oppose adaptation and speciation. In some cases, interspecific hybridisation is very common, making it surprising that species identity is preserved despite active gene exchange. The genomes of most eukaryotic species are highly heterogeneous with regard to gene density, abundance of repetitive DNA, chromatin compactisation etc, which can make certain genomic regions more prone or more resistant to introgression of genetic material from other species. Heterogeneity in local recombination rate underpins many of the observed patterns across the genome (e.g. actively recombining regions are typically gene rich and depleted for repetitive DNA) and it can strongly affect the permeability of genomic regions to interspecific introgression. The larger the region lacking recombination, the higher the chance for the presence of species incompatibility gene(s) in that region, making the entire non- or rarely recombining block impermeable to interspecific introgression. Large plant genomes tend to have highly heterogeneous recombination landscape, with recombination frequently occurring at the ends of the chromosomes and central regions lacking recombination. In this paper we review the relationship between recombination and introgression in plants and argue that large rarely recombining regions likely play a major role in preserving species identity in actively hybridising plant species.
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Affiliation(s)
- Edgar L. Y. Wong
- Department of Biology, University of Oxford, Oxford, United Kingdom
- Senckenberg Biodiversity and Climate Research Centre, Frankfurt am Main, Germany
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19
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Dagilis AJ, Matute DR. The fitness of an introgressing haplotype changes over the course of divergence and depends on its size and genomic location. PLoS Biol 2023; 21:e3002185. [PMID: 37459351 PMCID: PMC10374083 DOI: 10.1371/journal.pbio.3002185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 07/27/2023] [Accepted: 06/06/2023] [Indexed: 07/28/2023] Open
Abstract
The genomic era has made clear that introgression, or the movement of genetic material between species, is a common feature of evolution. Examples of both adaptive and deleterious introgression exist in a variety of systems. What is unclear is how the fitness of an introgressing haplotype changes as species diverge or as the size of the introgressing haplotype changes. In a simple model, we show that introgression may more easily occur into parts of the genome which have not diverged heavily from a common ancestor. The key insight is that alleles from a shared genetic background are likely to have positive epistatic interactions, increasing the fitness of a larger introgressing block. In regions of the genome where few existing substitutions are disrupted, this positive epistasis can be larger than incompatibilities with the recipient genome. Further, we show that early in the process of divergence, introgression of large haplotypes can be favored more than introgression of individual alleles. This model is consistent with observations of a positive relationship between recombination rate and introgression frequency across the genome; however, it generates several novel predictions. First, the model suggests that the relationship between recombination rate and introgression may not exist, or may be negative, in recently diverged species pairs. Furthermore, the model suggests that introgression that replaces existing derived variation will be more deleterious than introgression at sites carrying ancestral variants. These predictions are tested in an example of introgression in Drosophila melanogaster, with some support for both. Finally, the model provides a potential alternative explanation to asymmetry in the direction of introgression, with expectations of higher introgression from rapidly diverged populations into slowly evolving ones.
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Affiliation(s)
- Andrius J Dagilis
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Daniel R Matute
- Biology Department, University of North Carolina, Chapel Hill, North Carolina, United States of America
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20
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Rong S, Neil CR, Welch A, Duan C, Maguire S, Meremikwu IC, Meyerson M, Evans BJ, Fairbrother WG. Large-scale functional screen identifies genetic variants with splicing effects in modern and archaic humans. Proc Natl Acad Sci U S A 2023; 120:e2218308120. [PMID: 37192163 PMCID: PMC10214146 DOI: 10.1073/pnas.2218308120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 04/12/2023] [Indexed: 05/18/2023] Open
Abstract
Humans coexisted and interbred with other hominins which later became extinct. These archaic hominins are known to us only through fossil records and for two cases, genome sequences. Here, we engineer Neanderthal and Denisovan sequences into thousands of artificial genes to reconstruct the pre-mRNA processing patterns of these extinct populations. Of the 5,169 alleles tested in this massively parallel splicing reporter assay (MaPSy), we report 962 exonic splicing mutations that correspond to differences in exon recognition between extant and extinct hominins. Using MaPSy splicing variants, predicted splicing variants, and splicing quantitative trait loci, we show that splice-disrupting variants experienced greater purifying selection in anatomically modern humans than that in Neanderthals. Adaptively introgressed variants were enriched for moderate-effect splicing variants, consistent with positive selection for alternative spliced alleles following introgression. As particularly compelling examples, we characterized a unique tissue-specific alternative splicing variant at the adaptively introgressed innate immunity gene TLR1, as well as a unique Neanderthal introgressed alternative splicing variant in the gene HSPG2 that encodes perlecan. We further identified potentially pathogenic splicing variants found only in Neanderthals and Denisovans in genes related to sperm maturation and immunity. Finally, we found splicing variants that may contribute to variation among modern humans in total bilirubin, balding, hemoglobin levels, and lung capacity. Our findings provide unique insights into natural selection acting on splicing in human evolution and demonstrate how functional assays can be used to identify candidate causal variants underlying differences in gene regulation and phenotype.
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Affiliation(s)
- Stephen Rong
- Center for Computational Molecular Biology, Brown University, Providence, RI02912
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Christopher R. Neil
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Anastasia Welch
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Chaorui Duan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Samantha Maguire
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Ijeoma C. Meremikwu
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Malcolm Meyerson
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
| | - Ben J. Evans
- Department of Biology, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - William G. Fairbrother
- Center for Computational Molecular Biology, Brown University, Providence, RI02912
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI02912
- Hassenfeld Child Health Innovation Institute of Brown University, Providence, RI02912
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21
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Wei X, Robles CR, Pazokitoroudi A, Ganna A, Gusev A, Durvasula A, Gazal S, Loh PR, Reich D, Sankararaman S. The lingering effects of Neanderthal introgression on human complex traits. eLife 2023; 12:e80757. [PMID: 36939312 PMCID: PMC10076017 DOI: 10.7554/elife.80757] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 03/17/2023] [Indexed: 03/21/2023] Open
Abstract
The genetic variants introduced into the ancestors of modern humans from interbreeding with Neanderthals have been suggested to contribute an unexpected extent to complex human traits. However, testing this hypothesis has been challenging due to the idiosyncratic population genetic properties of introgressed variants. We developed rigorous methods to assess the contribution of introgressed Neanderthal variants to heritable trait variation and applied these methods to analyze 235,592 introgressed Neanderthal variants and 96 distinct phenotypes measured in about 300,000 unrelated white British individuals in the UK Biobank. Introgressed Neanderthal variants make a significant contribution to trait variation (explaining 0.12% of trait variation on average). However, the contribution of introgressed variants tends to be significantly depleted relative to modern human variants matched for allele frequency and linkage disequilibrium (about 59% depletion on average), consistent with purifying selection on introgressed variants. Different from previous studies (McArthur et al., 2021), we find no evidence for elevated heritability across the phenotypes examined. We identified 348 independent significant associations of introgressed Neanderthal variants with 64 phenotypes. Previous work (Skov et al., 2020) has suggested that a majority of such associations are likely driven by statistical association with nearby modern human variants that are the true causal variants. Applying a customized fine-mapping led us to identify 112 regions across 47 phenotypes containing 4303 unique genetic variants where introgressed variants are highly likely to have a phenotypic effect. Examination of these variants reveals their substantial impact on genes that are important for the immune system, development, and metabolism.
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Affiliation(s)
- Xinzhu Wei
- Department of Computational Biology, Cornell UniversityNew YorkUnited States
| | - Christopher R Robles
- Department of Human Genetics, University of California, Los AngelesLos AngelesUnited States
| | - Ali Pazokitoroudi
- Department of Computer Science, University of California, Los AngelesLos AngelesUnited States
| | - Andrea Ganna
- Analytical and Translational Genetics Unit, Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Program in Medical and Population Genetics, Broad Institute of MIT and HarvardCambridgeUnited States
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Alexander Gusev
- Dana-Farber Cancer Institute, Harvard Medical SchoolBostonUnited States
| | - Arun Durvasula
- Department of Genetics, Harvard Medical SchoolBostonUnited States
- Department of Human Evolutionary Biology, Harvard UniversityCambridgeUnited States
| | - Steven Gazal
- Center for Genetic Epidemiology, Department of Public and Population Health Sciences, University of Southern CaliforniaLos AngelesUnited States
- Division of Genetics,Department of Medicine, Brigham and Women’s Hospital, Harvard Medical SchoolBostonUnited States
| | - Po-Ru Loh
- Program in Medical and Population Genetics, Broad Institute of MIT and HarvardCambridgeUnited States
| | - David Reich
- Program in Medical and Population Genetics, Broad Institute of MIT and HarvardCambridgeUnited States
- Department of Genetics, Harvard Medical SchoolBostonUnited States
- Department of Human Evolutionary Biology, Harvard UniversityCambridgeUnited States
- Howard Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Sriram Sankararaman
- Department of Human Genetics, University of California, Los AngelesLos AngelesUnited States
- Department of Computer Science, University of California, Los AngelesLos AngelesUnited States
- Department of Computational Medicine, University of California, Los AngelesLos AngelesUnited States
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22
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Pathogenic Variants Associated with Rare Monogenic Diseases Established in Ancient Neanderthal and Denisovan Genome-Wide Data. Genes (Basel) 2023; 14:genes14030727. [PMID: 36980999 PMCID: PMC10048696 DOI: 10.3390/genes14030727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
Ancient anatomically modern humans (AMHs) encountered other archaic human species, most notably Neanderthals and Denisovans, when they left Africa and spread across Europe and Asia ~60,000 years ago. They interbred with them, and modern human genomes retain DNA inherited from these interbreeding events. High quality (high coverage) ancient human genomes have recently been sequenced allowing for a direct estimation of individual heterozygosity, which has shown that genetic diversity in these archaic human groups was very low, indicating low population sizes. In this study, we analyze ten ancient human genome-wide data, including four sequenced with high-coverage. We screened these ancient genome-wide data for pathogenic mutations associated with monogenic diseases, and established unusual aggregation of pathogenic mutations in individual subjects, including quadruple homozygous cases of pathogenic variants in the PAH gene associated with the condition phenylketonuria in a ~120,000 years old Neanderthal. Such aggregation of pathogenic mutations is extremely rare in contemporary populations, and their existence in ancient humans could be explained by less significant clinical manifestations coupled with small community sizes, leading to higher inbreeding levels. Our results suggest that pathogenic variants associated with rare diseases might be the result of introgression from other archaic human species, and archaic admixture thus could have influenced disease risk in modern humans.
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23
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Zhang X, Kim B, Singh A, Sankararaman S, Durvasula A, Lohmueller KE. MaLAdapt Reveals Novel Targets of Adaptive Introgression From Neanderthals and Denisovans in Worldwide Human Populations. Mol Biol Evol 2023; 40:msad001. [PMID: 36617238 PMCID: PMC9887621 DOI: 10.1093/molbev/msad001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 12/25/2022] [Accepted: 12/28/2022] [Indexed: 01/09/2023] Open
Abstract
Adaptive introgression (AI) facilitates local adaptation in a wide range of species. Many state-of-the-art methods detect AI with ad-hoc approaches that identify summary statistic outliers or intersect scans for positive selection with scans for introgressed genomic regions. Although widely used, approaches intersecting outliers are vulnerable to a high false-negative rate as the power of different methods varies, especially for complex introgression events. Moreover, population genetic processes unrelated to AI, such as background selection or heterosis, may create similar genomic signals to AI, compromising the reliability of methods that rely on neutral null distributions. In recent years, machine learning (ML) methods have been increasingly applied to population genetic questions. Here, we present a ML-based method called MaLAdapt for identifying AI loci from genome-wide sequencing data. Using an Extra-Trees Classifier algorithm, our method combines information from a large number of biologically meaningful summary statistics to capture a powerful composite signature of AI across the genome. In contrast to existing methods, MaLAdapt is especially well-powered to detect AI with mild beneficial effects, including selection on standing archaic variation, and is robust to non-AI selective sweeps, heterosis from deleterious mutations, and demographic misspecification. Furthermore, MaLAdapt outperforms existing methods for detecting AI based on the analysis of simulated data and the validation of empirical signals through visual inspection of haplotype patterns. We apply MaLAdapt to the 1000 Genomes Project human genomic data and discover novel AI candidate regions in non-African populations, including genes that are enriched in functionally important biological pathways regulating metabolism and immune responses.
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Affiliation(s)
- Xinjun Zhang
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA
| | - Bernard Kim
- Department of Biology, Stanford University, Palo Alto, CA
| | - Armaan Singh
- Department of Computer Science, UCLA, Los Angeles, CA
| | - Sriram Sankararaman
- Department of Computer Science, UCLA, Los Angeles, CA
- Department of Computational Medicine, UCLA, Los Angeles, CA
- Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Arun Durvasula
- Department of Genetics, Harvard Medical School, Boston, MA
| | - Kirk E Lohmueller
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, CA
- Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, CA
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24
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Schroeder L, Ackermann RR. Moving beyond the adaptationist paradigm for human evolution, and why it matters. J Hum Evol 2023; 174:103296. [PMID: 36527977 DOI: 10.1016/j.jhevol.2022.103296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 11/12/2022] [Accepted: 11/12/2022] [Indexed: 12/23/2022]
Abstract
The Journal of Human Evolution (JHE) was founded 50 years ago when much of the foundation for how we think about human evolution was in place or being put in place, providing the main framework for how we consider our origins today. Here, we will explore historical developments, including early JHE outputs, as they relate to our understanding of the relationship between phenotypic variation and evolutionary process, and use that as a springboard for considering our current understanding of these links as applied to human evolution. We will focus specifically on how the study of variation itself has shifted us away from taxonomic and adaptationist perspectives toward a richer understanding of the processes shaping human evolutionary history, using literature searches and specific test cases to highlight this. We argue that natural selection, gene exchange, genetic drift, and mutation should not be considered individually when considering the production of hominin diversity. In this context, we offer suggestions for future research directions and reflect on this more complex understanding of human evolution and its broader relevance to society. Finally, we end by considering authorship demographics and practices in the last 50 years within JHE and how a shift in these demographics has the potential to reshape the science of human evolution going forward.
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Affiliation(s)
- Lauren Schroeder
- Department of Anthropology, University of Toronto Mississauga, Mississauga, ON, L5L 1C6, Canada; Human Evolution Research Institute, University of Cape Town, Rondebosch, 7701, South Africa.
| | - Rebecca Rogers Ackermann
- Human Evolution Research Institute, University of Cape Town, Rondebosch, 7701, South Africa; Department of Archaeology, University of Cape Town, Rondebosch, 7701, South Africa.
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25
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Nouhaud P, Martin SH, Portinha B, Sousa VC, Kulmuni J. Rapid and predictable genome evolution across three hybrid ant populations. PLoS Biol 2022; 20:e3001914. [PMID: 36538502 PMCID: PMC9767332 DOI: 10.1371/journal.pbio.3001914] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 11/14/2022] [Indexed: 12/24/2022] Open
Abstract
Hybridization is frequent in the wild but it is unclear when admixture events lead to predictable outcomes and if so, at what timescale. We show that selection led to correlated sorting of genetic variation rapidly after admixture in 3 hybrid Formica aquilonia × F. polyctena ant populations. Removal of ancestry from the species with the lowest effective population size happened in all populations, consistent with purging of deleterious load. This process was modulated by recombination rate variation and the density of functional sites. Moreover, haplotypes with signatures of positive selection in either species were more likely to fix in hybrids. These mechanisms led to mosaic genomes with comparable ancestry proportions. Our work demonstrates predictable evolution over short timescales after admixture in nature.
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Affiliation(s)
- Pierre Nouhaud
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Simon H. Martin
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Beatriz Portinha
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
- cE3c, Centre for Ecology, Evolution and Environmental Changes, Department of Animal Biology, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - Vitor C. Sousa
- cE3c, Centre for Ecology, Evolution and Environmental Changes, Department of Animal Biology, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisboa, Portugal
| | - Jonna Kulmuni
- Organismal & Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
- Tvärminne Zoological Station, University of Helsinki, Hanko, Finland
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26
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vonHoldt BM, Brzeski KE, Aardema ML, Schell CJ, Rutledge LY, Fain SR, Shutt AC, Linderholm A, Murphy WJ. Persistence and expansion of cryptic endangered red wolf genomic ancestry along the American Gulf coast. Mol Ecol 2022; 31:5440-5454. [PMID: 34585803 DOI: 10.1111/mec.16200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 09/03/2021] [Accepted: 09/22/2021] [Indexed: 12/24/2022]
Abstract
Admixture and introgression play a critical role in adaptation and genetic rescue that has only recently gained a deeper appreciation. Here, we explored the geographical and genomic landscape of cryptic ancestry of the endangered red wolf that persists within the genome of a ubiquitous sister taxon, the coyote, all while the red wolf has been extinct in the wild since the early 1980s. We assessed admixture across 120,621 single nucleotiode polymorphism (SNP) loci genotyped in 293 canid genomes. We found support for increased red wolf ancestry along a west-to-east gradient across the southern United States associated with historical admixture in the past 100 years. Southwestern Louisiana and southeastern Texas, the geographical zone where the last red wolves were known prior to extinction in the wild, contained the highest and oldest levels of red wolf ancestry. Further, given the paucity of inferences based on chromosome types, we compared patterns of ancestry on the X chromosome and autosomes. We additionally aimed to explore the relationship between admixture timing and recombination rate variation to investigate gene flow events. We found that X-linked regions of low recombination rates were depleted of introgression, relative to the autosomes, consistent with the large X effect and enrichment with loci involved in maintaining reproductive isolation. Recombination rate was positively correlated with red wolf ancestry across coyote genomes, consistent with theoretical predictions. The geographical and genomic extent of cryptic red wolf ancestry can provide novel genomic resources for recovery plans targeting the conservation of the endangered red wolf.
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Affiliation(s)
- Bridgett M vonHoldt
- Ecology & Evolutionary Biology, Princeton University, Princeton, New Jersey, USA
| | - Kristin E Brzeski
- College of Forest Resources and Environment Science, Michigan Technological University, Houghton, Michigan, USA
| | - Matthew L Aardema
- Department of Biology, Montclair State University, Montclair, New Jersey, USA.,Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, USA
| | - Christopher J Schell
- Department of Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, California, USA
| | - Linda Y Rutledge
- Biology Department, Trent University, Peterborough, Ontario, Canada
| | - Steven R Fain
- USFWS, Clark R. Bavin National Forensics Laboratory, Ashland, Oregon, USA
| | | | - Anna Linderholm
- Department of Anthropology, Texas A&M University, College Station, Texas, USA
| | - William J Murphy
- Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
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Harvati K, Ackermann RR. Merging morphological and genetic evidence to assess hybridization in Western Eurasian late Pleistocene hominins. Nat Ecol Evol 2022; 6:1573-1585. [PMID: 36064759 DOI: 10.1038/s41559-022-01875-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/08/2022] [Indexed: 11/09/2022]
Abstract
Previous scientific consensus saw human evolution as defined by adaptive differences (behavioural and/or biological) and the emergence of Homo sapiens as the ultimate replacement of non-modern groups by a modern, adaptively more competitive group. However, recent research has shown that the process underlying our origins was considerably more complex. While archaeological and fossil evidence suggests that behavioural complexity may not be confined to the modern human lineage, recent palaeogenomic work shows that gene flow between distinct lineages (for example, Neanderthals, Denisovans, early H. sapiens) occurred repeatedly in the late Pleistocene, probably contributing elements to our genetic make-up that might have been crucial to our success as a diverse, adaptable species. Following these advances, the prevailing human origins model has shifted from one of near-complete replacement to a more nuanced view of partial replacement with considerable reticulation. Here we provide a brief introduction to the current genetic evidence for hybridization among hominins, its prevalence in, and effects on, comparative mammal groups, and especially how it manifests in the skull. We then explore the degree to which cranial variation seen in the fossil record of late Pleistocene hominins from Western Eurasia corresponds with our current genetic and comparative data. We are especially interested in understanding the degree to which skeletal data can reflect admixture. Our findings indicate some correspondence between these different lines of evidence, flag individual fossils as possibly admixed, and suggest that different cranial regions may preserve hybridization signals differentially. We urge further studies of the phenotype to expand our ability to detect the ways in which migration, interaction and genetic exchange have shaped the human past, beyond what is currently visible with the lens of ancient DNA.
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Affiliation(s)
- K Harvati
- Paleoanthropology section, Senckenberg Centre for Human Evolution and Palaeoenvironment, Institute for Archaeological Sciences, Eberhard Karls Universität Tübingen, Tübingen, Germany.
- DFG Centre for Advanced Studies 'Words, Bones, Genes, Tools', Eberhard Karls Universität Tübingen, Tübingen, Germany.
| | - R R Ackermann
- Human Evolution Research Institute, University of Cape Town, Cape Town, South Africa.
- Department of Archaeology, University of Cape Town, Cape Town, South Africa.
- DFG Centre for Advanced Studies 'Words, Bones, Genes, Tools', Eberhard Karls Universität Tübingen, Tübingen, Germany.
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28
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Reilly PF, Tjahjadi A, Miller SL, Akey JM, Tucci S. The contribution of Neanderthal introgression to modern human traits. Curr Biol 2022; 32:R970-R983. [PMID: 36167050 PMCID: PMC9741939 DOI: 10.1016/j.cub.2022.08.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neanderthals, our closest extinct relatives, lived in western Eurasia from 400,000 years ago until they went extinct around 40,000 years ago. DNA retrieved from ancient specimens revealed that Neanderthals mated with modern human contemporaries. As a consequence, introgressed Neanderthal DNA survives scattered across the human genome such that 1-4% of the genome of present-day people outside Africa are inherited from Neanderthal ancestors. Patterns of Neanderthal introgressed genomic sequences suggest that Neanderthal alleles had distinct fates in the modern human genetic background. Some Neanderthal alleles facilitated human adaptation to new environments such as novel climate conditions, UV exposure levels and pathogens, while others had deleterious consequences. Here, we review the body of work on Neanderthal introgression over the past decade. We describe how evolutionary forces shaped the genomic landscape of Neanderthal introgression and highlight the impact of introgressed alleles on human biology and phenotypic variation.
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Affiliation(s)
| | - Audrey Tjahjadi
- Department of Anthropology, Yale University, New Haven, CT, USA
| | | | - Joshua M Akey
- Lewis Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
| | - Serena Tucci
- Department of Anthropology, Yale University, New Haven, CT, USA; Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, USA.
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29
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Muralidhar P, Coop G, Veller C. Assortative mating enhances postzygotic barriers to gene flow via ancestry bundling. Proc Natl Acad Sci U S A 2022; 119:e2122179119. [PMID: 35858444 PMCID: PMC9335313 DOI: 10.1073/pnas.2122179119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 06/06/2022] [Indexed: 01/21/2023] Open
Abstract
Hybridization and subsequent genetic introgression are now known to be common features of the histories of many species, including our own. Following hybridization, selection often purges introgressed DNA genome-wide. While assortative mating can limit hybridization in the first place, it is also known to play an important role in postzygotic selection against hybrids and, thus, the purging of introgressed DNA. However, this role is usually thought of as a direct one: a tendency for mates to be conspecific reduces the sexual fitness of hybrids, reducing the transmission of introgressed ancestry. Here, we explore a second, indirect role of assortative mating as a postzygotic barrier to gene flow. Under assortative mating, parents covary in their ancestry, causing ancestry to be "bundled" in their offspring and later generations. This bundling effect increases ancestry variance in the population, enhancing the efficiency with which postzygotic selection purges introgressed DNA. Using whole-genome simulations, we show that the bundling effect can comprise a substantial portion of mate choice's overall effect as a postzygotic barrier to gene flow. We then derive a simple method for estimating the impact of the bundling effect from standard metrics of assortative mating. Applying this method to data from a diverse set of hybrid zones, we find that the bundling effect increases the purging of introgressed DNA by between 1.2-fold (in a baboon system with weak assortative mating) and 14-fold (in a swordtail system with strong assortative mating). Thus, assortative mating's bundling effect contributes substantially to the genetic isolation of species.
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Affiliation(s)
- Pavitra Muralidhar
- Department of Evolution and Ecology, University of California, 95616 Davis, CA
- Center for Population Biology, University of California, 95616 Davis, CA
| | - Graham Coop
- Department of Evolution and Ecology, University of California, 95616 Davis, CA
- Center for Population Biology, University of California, 95616 Davis, CA
| | - Carl Veller
- Department of Evolution and Ecology, University of California, 95616 Davis, CA
- Center for Population Biology, University of California, 95616 Davis, CA
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30
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Duranton M, Pool JE. Interactions between natural selection and recombination shape the genomic landscape of introgression. Mol Biol Evol 2022; 39:6603329. [PMID: 35666817 PMCID: PMC9317171 DOI: 10.1093/molbev/msac122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hybridization between lineages that have not reached complete reproductive isolation appears more and more like a common phenomenon. Indeed, speciation genomics studies have now extensively shown that many species' genomes have hybrid ancestry. However, genomic patterns of introgression are often heterogeneous across the genome. In many organisms, a positive correlation between introgression levels and recombination rate has been observed. It is usually explained by the purging of deleterious introgressed material due to incompatibilities. However, the opposite relationship was observed in a North American population of Drosophila melanogaster with admixed European and African ancestry. In order to explore how directional and epistatic selection can impact the relationship between introgression and recombination, we performed forward simulations of whole D. melanogaster genomes reflecting the North American population's history. Our results revealed that the simplest models of positive selection often yield negative correlations between introgression and recombination such as the one observed in D. melanogaster. We also confirmed that incompatibilities tend to produce positive introgression-recombination correlations. And yet, we identify parameter space under each model where the predicted correlation is reversed. These findings deepen our understanding of the evolutionary forces that may shape patterns of ancestry across genomes, and they strengthen the foundation for future studies aimed at estimating genome-wide parameters of selection in admixed populations.
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Affiliation(s)
- Maud Duranton
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - John E Pool
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
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31
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Brand CM, Colbran LL, Capra JA. Predicting Archaic Hominin Phenotypes from Genomic Data. Annu Rev Genomics Hum Genet 2022; 23:591-612. [PMID: 35440148 DOI: 10.1146/annurev-genom-111521-121903] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ancient DNA provides a powerful window into the biology of extant and extinct species, including humans' closest relatives: Denisovans and Neanderthals. Here, we review what is known about archaic hominin phenotypes from genomic data and how those inferences have been made. We contend that understanding the influence of variants on lower-level molecular phenotypes-such as gene expression and protein function-is a promising approach to using ancient DNA to learn about archaic hominin traits. Molecular phenotypes have simpler genetic architectures than organism-level complex phenotypes, and this approach enables moving beyond association studies by proposing hypotheses about the effects of archaic variants that are testable in model systems. The major challenge to understanding archaic hominin phenotypes is broadening our ability to accurately map genotypes to phenotypes, but ongoing advances ensure that there will be much more to learn about archaic hominin phenotypes from their genomes. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Colin M Brand
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA; , .,Bakar Computational Health Sciences Institute, University of California, San Francisco, California, USA
| | - Laura L Colbran
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John A Capra
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA; , .,Bakar Computational Health Sciences Institute, University of California, San Francisco, California, USA
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32
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Witt KE, Villanea F, Loughran E, Zhang X, Huerta-Sanchez E. Apportioning archaic variants among modern populations. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200411. [PMID: 35430882 PMCID: PMC9014186 DOI: 10.1098/rstb.2020.0411] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The apportionment of human genetic diversity within and between populations has been measured to understand human relatedness and demographic history. Likewise, the distribution of archaic ancestry in modern populations can be leveraged to better understand the interaction between our species and its archaic relatives. Resolving the interactions between modern and archaic human populations can be difficult, as archaic variants in modern populations have been shaped by genetic drift, bottlenecks and gene flow. Here, we investigate the distribution of archaic variation in Eurasian populations. We find that archaic ancestry coverage at the individual- and population-level present distinct patterns in modern human populations: South Asians have nearly twice the number of population-unique archaic alleles compared with Europeans or East Asians, indicating that these populations experienced differing demographic and archaic admixture events. We confirm previous observations that East Asian individuals have more Neanderthal ancestry than European individuals, but surprisingly, when we compare the number of single nucleotide polymorphisms with archaic alleles found across a population, Europeans have more Neanderthal ancestry than East Asians. We compare these results to simulated models and conclude that these patterns are consistent with multiple admixture events between modern humans and Neanderthals. This article is part of the theme issue ‘Celebrating 50 years since Lewontin's apportionment of human diversity’.
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Affiliation(s)
- Kelsey E. Witt
- Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
- Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA
| | - Fernando Villanea
- Department of Anthropology, University of Colorado Boulder, Boulder, CO, USA
| | - Elle Loughran
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Republic of Ireland
| | - Xinjun Zhang
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Emilia Huerta-Sanchez
- Ecology, Evolution, and Organismal Biology, Brown University, Providence, RI 02912, USA
- Center for Computational Molecular Biology, Brown University, Providence, RI 02912, USA
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Republic of Ireland
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33
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MacPherson A, Wang S, Yamaguchi R, Rieseberg L, Otto S. Parental Population Range Expansion Before Secondary Contact Promotes Heterosis. Am Nat 2022; 200:E1-E15. [DOI: 10.1086/719656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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34
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Dittberner H, Tellier A, de Meaux J. Approximate Bayesian computation untangles signatures of contemporary and historical hybridization between two endangered species. Mol Biol Evol 2022; 39:6516021. [PMID: 35084503 PMCID: PMC8826969 DOI: 10.1093/molbev/msac015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Contemporary gene flow, when resumed after a period of isolation, can have crucial consequences for endangered species, as it can both increase the supply of adaptive alleles and erode local adaptation. Determining the history of gene flow and thus the importance of contemporary hybridization, however, is notoriously difficult. Here, we focus on two endangered plant species, Arabis nemorensis and A. sagittata, which hybridize naturally in a sympatric population located on the banks of the Rhine. Using reduced genome sequencing, we determined the phylogeography of the two taxa but report only a unique sympatric population. Molecular variation in chloroplast DNA indicated that A. sagittata is the principal receiver of gene flow. Applying classical D-statistics and its derivatives to whole-genome data of 35 accessions, we detect gene flow not only in the sympatric population but also among allopatric populations. Using an Approximate Bayesian computation approach, we identify the model that best describes the history of gene flow between these taxa. This model shows that low levels of gene flow have persisted long after speciation. Around 10 000 years ago, gene flow stopped and a period of complete isolation began. Eventually, a hotspot of contemporary hybridization was formed in the unique sympatric population. Occasional sympatry may have helped protect these lineages from extinction in spite of their extremely low diversity.
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Affiliation(s)
- Hannes Dittberner
- Institute of Plant Sciences,University of Cologne, Zülpicher str. 47b, Germany
| | - Aurelien Tellier
- Department of Life Science Systems, Technical University of Munich, Freising, Germany
| | - Juliette de Meaux
- Institute of Plant Sciences,University of Cologne, Zülpicher str. 47b, Germany
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35
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Banker SE, Bonhomme F, Nachman MW. Bidirectional introgression between Mus musculus domesticus and Mus spretus. Genome Biol Evol 2022; 14:6509516. [PMID: 35038727 PMCID: PMC8784167 DOI: 10.1093/gbe/evab288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/22/2021] [Indexed: 11/24/2022] Open
Abstract
Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles—including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
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Affiliation(s)
- Sarah E Banker
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, 94720, USA
| | - François Bonhomme
- Institut des Sciences de l'Evolution, Université de Montpellier, Montpellier, France
| | - Michael W Nachman
- Department of Integrative Biology and Museum of Vertebrate Zoology, University of California, Berkeley, Berkeley, CA, 94720, USA
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36
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Liu S, Zhang L, Sang Y, Lai Q, Zhang X, Jia C, Long Z, Wu J, Ma T, Mao K, Street NR, Ingvarsson PK, Liu J, Wang J. Demographic history and natural selection shape patterns of deleterious mutation load and barriers to introgression across Populus genome. Mol Biol Evol 2022; 39:6505222. [PMID: 35022759 PMCID: PMC8826634 DOI: 10.1093/molbev/msac008] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Hybridization and resulting introgression are important processes shaping the tree of life and appear to be far more common than previously thought. However, how the genome evolution was shaped by various genetic and evolutionary forces after hybridization remains unresolved. Here we used whole-genome resequencing data of 227 individuals from multiple widespread Populus species to characterize their contemporary patterns of hybridization and to quantify genomic signatures of past introgression. We observe a high frequency of contemporary hybridization and confirm that multiple previously ambiguous species are in fact F1 hybrids. Seven species were identified, which experienced different demographic histories that resulted in strikingly varied efficacy of selection and burdens of deleterious mutations. Frequent past introgression has been found to be a pervasive feature throughout the speciation of these Populus species. The retained introgressed regions, more generally, tend to contain reduced genetic load and to be located in regions of high recombination. We also find that in pairs of species with substantial differences in effective population size, introgressed regions are inferred to have undergone selective sweeps at greater than expected frequencies in the species with lower effective population size, suggesting that introgression likely have higher potential to provide beneficial variation for species with small populations. Our results, therefore, illustrate that demography and recombination have interplayed with both positive and negative selection in determining the genomic evolution after hybridization.
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Affiliation(s)
- Shuyu Liu
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Lei Zhang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Yupeng Sang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Qiang Lai
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Xinxin Zhang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Changfu Jia
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Zhiqin Long
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Jiali Wu
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Tao Ma
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Kangshan Mao
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Nathaniel R Street
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Pär K Ingvarsson
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jianquan Liu
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
| | - Jing Wang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Science & State Key Lab of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, China
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37
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Suvorov A, Kim BY, Wang J, Armstrong EE, Peede D, D'Agostino ERR, Price DK, Waddell P, Lang M, Courtier-Orgogozo V, David JR, Petrov D, Matute DR, Schrider DR, Comeault AA. Widespread introgression across a phylogeny of 155 Drosophila genomes. Curr Biol 2022; 32:111-123.e5. [PMID: 34788634 PMCID: PMC8752469 DOI: 10.1016/j.cub.2021.10.052] [Citation(s) in RCA: 91] [Impact Index Per Article: 45.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/29/2021] [Accepted: 10/22/2021] [Indexed: 01/12/2023]
Abstract
Genome-scale sequence data have invigorated the study of hybridization and introgression, particularly in animals. However, outside of a few notable cases, we lack systematic tests for introgression at a larger phylogenetic scale across entire clades. Here, we leverage 155 genome assemblies from 149 species to generate a fossil-calibrated phylogeny and conduct multilocus tests for introgression across 9 monophyletic radiations within the genus Drosophila. Using complementary phylogenomic approaches, we identify widespread introgression across the evolutionary history of Drosophila. Mapping gene-tree discordance onto the phylogeny revealed that both ancient and recent introgression has occurred across most of the 9 clades that we examined. Our results provide the first evidence of introgression occurring across the evolutionary history of Drosophila and highlight the need to continue to study the evolutionary consequences of hybridization and introgression in this genus and across the tree of life.
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Affiliation(s)
- Anton Suvorov
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Bernard Y Kim
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Jeremy Wang
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | - David Peede
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | - Donald K Price
- School of Life Sciences, University of Nevada, Las Vegas, NV 89119, USA
| | - Peter Waddell
- School of Fundamental Sciences, Massey University, Palmerston North 4442, New Zealand
| | - Michael Lang
- CNRS, Institut Jacques Monod, Université de Paris, Paris 75013, France
| | | | - Jean R David
- Laboratoire Evolution, Génomes, Comportement, Ecologie (EGCE) CNRS, IRD, Univ. Paris-sud, Université Paris-Saclay, Gif sur Yvette 91190, France; Institut de Systématique, Evolution, Biodiversité, CNRS, MNHN, UPMC, EPHE, Muséum National d'Histoire Naturelle, Sorbonne Universités, Paris 75005, France
| | - Dmitri Petrov
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Daniel R Matute
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Daniel R Schrider
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Aaron A Comeault
- Molecular Ecology & Evolution Group, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2DGA, UK.
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38
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Jagoda E, Xue JR, Reilly SK, Dannemann M, Racimo F, Huerta-Sanchez E, Sankararaman S, Kelso J, Pagani L, Sabeti PC, Capellini TD. Detection of Neanderthal Adaptively Introgressed Genetic Variants That Modulate Reporter Gene Expression in Human Immune Cells. Mol Biol Evol 2022; 39:msab304. [PMID: 34662402 PMCID: PMC8760939 DOI: 10.1093/molbev/msab304] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although some variation introgressed from Neanderthals has undergone selective sweeps, little is known about its functional significance. We used a Massively Parallel Reporter Assay (MPRA) to assay 5,353 high-frequency introgressed variants for their ability to modulate the gene expression within 170 bp of endogenous sequence. We identified 2,548 variants in active putative cis-regulatory elements (CREs) and 292 expression-modulating variants (emVars). These emVars are predicted to alter the binding motifs of important immune transcription factors, are enriched for associations with neutrophil and white blood cell count, and are associated with the expression of genes that function in innate immune pathways including inflammatory response and antiviral defense. We combined the MPRA data with other data sets to identify strong candidates to be driver variants of positive selection including an emVar that may contribute to protection against severe COVID-19 response. We endogenously deleted two CREs containing expression-modulation variants linked to immune function, rs11624425 and rs80317430, identifying their primary genic targets as ELMSAN1, and PAN2 and STAT2, respectively, three genes differentially expressed during influenza infection. Overall, we present the first database of experimentally identified expression-modulating Neanderthal-introgressed alleles contributing to potential immune response in modern humans.
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Affiliation(s)
- Evelyn Jagoda
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - James R Xue
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Steven K Reilly
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Michael Dannemann
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
- Estonian Biocentre, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - Fernando Racimo
- Lundbeck GeoGenetics Centre, The Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Emilia Huerta-Sanchez
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA
| | - Sriram Sankararaman
- Department of Computer Science, UCLA, Los Angeles, CA, USA
- Department of Human Genetics, UCLA, Los Angeles, CA, USA
| | - Janet Kelso
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Luca Pagani
- Estonian Biocentre, Institute of Genomics, University of Tartu, Tartu, Estonia
- Department of Biology, University of Padova, Padova, Italy
| | - Pardis C Sabeti
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Terence D Capellini
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
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39
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Langdon QK, Powell DL, Kim B, Banerjee SM, Payne C, Dodge TO, Moran B, Fascinetto-Zago P, Schumer M. Predictability and parallelism in the contemporary evolution of hybrid genomes. PLoS Genet 2022; 18:e1009914. [PMID: 35085234 PMCID: PMC8794199 DOI: 10.1371/journal.pgen.1009914] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/28/2021] [Indexed: 12/28/2022] Open
Abstract
Hybridization between species is widespread across the tree of life. As a result, many species, including our own, harbor regions of their genome derived from hybridization. Despite the recognition that this process is widespread, we understand little about how the genome stabilizes following hybridization, and whether the mechanisms driving this stabilization tend to be shared across species. Here, we dissect the drivers of variation in local ancestry across the genome in replicated hybridization events between two species pairs of swordtail fish: Xiphophorus birchmanni × X. cortezi and X. birchmanni × X. malinche. We find unexpectedly high levels of repeatability in local ancestry across the two types of hybrid populations. This repeatability is attributable in part to the fact that the recombination landscape and locations of functionally important elements play a major role in driving variation in local ancestry in both types of hybrid populations. Beyond these broad scale patterns, we identify dozens of regions of the genome where minor parent ancestry is unusually low or high across species pairs. Analysis of these regions points to shared sites under selection across species pairs, and in some cases, shared mechanisms of selection. We show that one such region is a previously unknown hybrid incompatibility that is shared across X. birchmanni × X. cortezi and X. birchmanni × X. malinche hybrid populations.
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Affiliation(s)
- Quinn K. Langdon
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Daniel L. Powell
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Bernard Kim
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Shreya M. Banerjee
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Cheyenne Payne
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Tristram O. Dodge
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Ben Moran
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
| | - Paola Fascinetto-Zago
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Molly Schumer
- Department of Biology, Stanford University, Stanford, California, United States of America
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”, A.C., Calnali, Mexico
- Hanna H. Gray Fellow, Howard Hughes Medical Institutes, Chevy Chase, Maryland, United States of America
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40
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Maceda I, Lao O. Analysis of the Batch Effect Due to Sequencing Center in Population Statistics Quantifying Rare Events in the 1000 Genomes Project. Genes (Basel) 2021; 13:genes13010044. [PMID: 35052384 PMCID: PMC8775088 DOI: 10.3390/genes13010044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/19/2021] [Accepted: 12/21/2021] [Indexed: 12/01/2022] Open
Abstract
The 1000 Genomes Project (1000G) is one of the most popular whole genome sequencing datasets used in different genomics fields and has boosting our knowledge in medical and population genomics, among other fields. Recent studies have reported the presence of ghost mutation signals in the 1000G. Furthermore, studies have shown that these mutations can influence the outcomes of follow-up studies based on the genetic variation of 1000G, such as single nucleotide variants (SNV) imputation. While the overall effect of these ghost mutations can be considered negligible for common genetic variants in many populations, the potential bias remains unclear when studying low frequency genetic variants in the population. In this study, we analyze the effect of the sequencing center in predicted loss of function (LoF) alleles, the number of singletons, and the patterns of archaic introgression in the 1000G. Our results support previous studies showing that the sequencing center is associated with LoF and singletons independent of the population that is considered. Furthermore, we observed that patterns of archaic introgression were distorted for some populations depending on the sequencing center. When analyzing the frequency of SNPs showing extreme patterns of genotype differentiation among centers for CEU, YRI, CHB, and JPT, we observed that the magnitude of the sequencing batch effect was stronger at MAF < 0.2 and showed different profiles between CHB and the other populations. All these results suggest that data from 1000G must be interpreted with caution when considering statistics using variants at low frequency.
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Affiliation(s)
- Iago Maceda
- Population Genomics, CNAG-CRG, Centre for Genomic Regulation, 08028 Barcelona, Spain;
- Barcelona Institute of Science and Technology (BIST), 08036 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Oscar Lao
- Population Genomics, CNAG-CRG, Centre for Genomic Regulation, 08028 Barcelona, Spain;
- Barcelona Institute of Science and Technology (BIST), 08036 Barcelona, Spain
- Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
- Correspondence:
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41
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Abstract
Alleles that introgress between species can influence the evolutionary and ecological fate of species exposed to novel environments. Hybrid offspring of different species are often unfit, and yet it has long been argued that introgression can be a potent force in evolution, especially in plants. Over the last two decades, genomic data have increasingly provided evidence that introgression is a critically important source of genetic variation and that this additional variation can be useful in adaptive evolution of both animals and plants. Here, we review factors that influence the probability that foreign genetic variants provide long-term benefits (so-called adaptive introgression) and discuss their potential benefits. We find that introgression plays an important role in adaptive evolution, particularly when a species is far from its fitness optimum, such as when they expand their range or are subject to changing environments.
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Affiliation(s)
- Nathaniel B Edelman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA; .,Current affiliation: Yale Institute for Biospheric Studies and Yale School of the Environment, Yale University, New Haven, Connecticut 06511, USA;
| | - James Mallet
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA;
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42
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Blischak PD, Barker MS, Gutenkunst RN. Chromosome-scale inference of hybrid speciation and admixture with convolutional neural networks. Mol Ecol Resour 2021; 21:2676-2688. [PMID: 33682305 PMCID: PMC8675098 DOI: 10.1111/1755-0998.13355] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 01/26/2021] [Accepted: 02/05/2021] [Indexed: 11/30/2022]
Abstract
Inferring the frequency and mode of hybridization among closely related organisms is an important step for understanding the process of speciation and can help to uncover reticulated patterns of phylogeny more generally. Phylogenomic methods to test for the presence of hybridization come in many varieties and typically operate by leveraging expected patterns of genealogical discordance in the absence of hybridization. An important assumption made by these tests is that the data (genes or SNPs) are independent given the species tree. However, when the data are closely linked, it is especially important to consider their nonindependence. Recently, deep learning techniques such as convolutional neural networks (CNNs) have been used to perform population genetic inferences with linked SNPs coded as binary images. Here, we use CNNs for selecting among candidate hybridization scenarios using the tree topology (((P1 , P2 ), P3 ), Out) and a matrix of pairwise nucleotide divergence (dXY ) calculated in windows across the genome. Using coalescent simulations to train and independently test a neural network showed that our method, HyDe-CNN, was able to accurately perform model selection for hybridization scenarios across a wide breath of parameter space. We then used HyDe-CNN to test models of admixture in Heliconius butterflies, as well as comparing it to phylogeny-based introgression statistics. Given the flexibility of our approach, the dropping cost of long-read sequencing and the continued improvement of CNN architectures, we anticipate that inferences of hybridization using deep learning methods like ours will help researchers to better understand patterns of admixture in their study organisms.
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Affiliation(s)
- Paul D. Blischak
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Michael S. Barker
- Department of Ecology & Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
| | - Ryan N. Gutenkunst
- Department of Molecular & Cellular Biology, University of Arizona, Tucson, AZ, 85721, USA
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43
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Iasi LNM, Ringbauer H, Peter BM. An Extended Admixture Pulse Model Reveals the Limitations to Human-Neandertal Introgression Dating. Mol Biol Evol 2021; 38:5156-5174. [PMID: 34254144 PMCID: PMC8557420 DOI: 10.1093/molbev/msab210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neandertal DNA makes up 2-3% of the genomes of all non-African individuals. The patterns of Neandertal ancestry in modern humans have been used to estimate that this is the result of gene flow that occurred during the expansion of modern humans into Eurasia, but the precise dates of this event remain largely unknown. Here, we introduce an extended admixture pulse model that allows joint estimation of the timing and duration of gene flow. This model leads to simple expressions for both the admixture segment distribution and the decay curve of ancestry linkage disequilibrium, and we show that these two statistics are closely related. In simulations, we find that estimates of the mean time of admixture are largely robust to details in gene flow models, but that the duration of the gene flow can only be recovered if gene flow is very recent and the exact recombination map is known. These results imply that gene flow from Neandertals into modern humans could have happened over hundreds of generations. Ancient genomes from the time around the admixture event are thus likely required to resolve the question when, where, and for how long humans and Neandertals interacted.
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Affiliation(s)
- Leonardo N M Iasi
- Department of Evloutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Harald Ringbauer
- Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Benjamin M Peter
- Department of Evloutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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44
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Levi G, de Lombares C, Giuliani C, Iannuzzi V, Aouci R, Garagnani P, Franceschi C, Grimaud-Hervé D, Narboux-Nême N. DLX5/6 GABAergic Expression Affects Social Vocalization: Implications for Human Evolution. Mol Biol Evol 2021; 38:4748-4764. [PMID: 34132815 PMCID: PMC8557472 DOI: 10.1093/molbev/msab181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
DLX5 and DLX6 are two closely related transcription factors involved in brain development and in GABAergic differentiation. The DLX5/6 locus is regulated by FoxP2, a gene involved in language evolution and has been associated with neurodevelopmental disorders and mental retardation. Targeted inactivation of Dlx5/6 in mouse GABAergic neurons (Dlx5/6VgatCre mice) results in behavioral and metabolic phenotypes notably increasing lifespan by 33%. Here, we show that Dlx5/6VgatCre mice present a hyper-vocalization and hyper-socialization phenotype. While only 7% of control mice emitted more than 700 vocalizations/10 min, 30% and 56% of heterozygous or homozygous Dlx5/6VgatCre mice emitted more than 700 and up to 1,400 calls/10 min with a higher proportion of complex and modulated calls. Hyper-vocalizing animals were more sociable: the time spent in dynamic interactions with an unknown visitor was more than doubled compared to low-vocalizing individuals. The characters affected by Dlx5/6 in the mouse (sociability, vocalization, skull, and brain shape…) overlap those affected in the "domestication syndrome". We therefore explored the possibility that DLX5/6 played a role in human evolution and "self-domestication" comparing DLX5/6 genomic regions from Neanderthal and modern humans. We identified an introgressed Neanderthal haplotype (DLX5/6-N-Haplotype) present in 12.6% of European individuals that covers DLX5/6 coding and regulatory sequences. The DLX5/6-N-Haplotype includes the binding site for GTF2I, a gene associated with Williams-Beuren syndrome, a hyper-sociability and hyper-vocalization neurodevelopmental disorder. The DLX5/6-N-Haplotype is significantly underrepresented in semi-supercentenarians (>105 years of age), a well-established human model of healthy aging and longevity, suggesting their involvement in the coevolution of longevity, sociability, and speech.
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Affiliation(s)
- Giovanni Levi
- Physiologie Moléculaire et Adaptation, CNRS UMR7221, Département AVIV, Muséum National d'Histoire Naturelle, Paris, France
| | - Camille de Lombares
- Physiologie Moléculaire et Adaptation, CNRS UMR7221, Département AVIV, Muséum National d'Histoire Naturelle, Paris, France
| | - Cristina Giuliani
- Laboratory of Molecular Anthropology & Centre for Genome Biology, Department of Biological, Geological and Environmental Sciences, University of Bologna, Italy
| | - Vincenzo Iannuzzi
- Alma Mater Research Institute on Global Challenges and Climate Change, University of Bologna, Italy
| | - Rym Aouci
- Physiologie Moléculaire et Adaptation, CNRS UMR7221, Département AVIV, Muséum National d'Histoire Naturelle, Paris, France
| | - Paolo Garagnani
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, Italy
- Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet at Huddinge University Hospital, Stockholm, Sweden
| | - Claudio Franceschi
- Department of Experimental, Diagnostic and Specialty Medicine (DIMES), University of Bologna, Bologna, Italy
- Institute of Information Technologies, Mathematics and Mechanics, Lobachevsky University, Nizhniy Novgorod, Russia
| | - Dominique Grimaud-Hervé
- Histoire Naturelle de l’Homme Préhistorique, CNRS UMR 7194, Département H&E, Muséum National d'Histoire Naturelle, Paris, France
| | - Nicolas Narboux-Nême
- Physiologie Moléculaire et Adaptation, CNRS UMR7221, Département AVIV, Muséum National d'Histoire Naturelle, Paris, France
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45
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Analysis of whole exome sequencing in severe mental illness hints at selection of brain development and immune related genes. Sci Rep 2021; 11:21088. [PMID: 34702870 PMCID: PMC8548332 DOI: 10.1038/s41598-021-00123-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Accepted: 10/01/2021] [Indexed: 11/15/2022] Open
Abstract
Evolutionary trends may underlie some aspects of the risk for common, non-communicable disorders, including psychiatric disease. We analyzed whole exome sequencing data from 80 unique individuals from India coming from families with two or more individuals with severe mental illness. We used Population Branch Statistics (PBS) to identify variants and genes under positive selection and identified 74 genes as candidates for positive selection. Of these, 20 were previously associated with Schizophrenia, Alzheimer’s disease and cognitive abilities in genome wide association studies. We then checked whether any of these 74 genes were involved in common biological pathways or related to specific cellular or molecular functions. We found that immune related pathways and functions related to innate immunity such as antigen binding were over-represented. We also evaluated for the presence of Neanderthal introgressed segments in these genes and found Neanderthal introgression in a single gene out of the 74 candidate genes. However, the introgression pattern indicates the region is unlikely to be the source for selection. Our findings hint at how selection pressures in individuals from families with a history of severe mental illness may diverge from the general population. Further, it also provides insights into the genetic architecture of severe mental illness, such as schizophrenia and its link to immune factors.
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46
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Bisschop G, Lohse K, Setter D. Sweeps in time: leveraging the joint distribution of branch lengths. Genetics 2021; 219:iyab119. [PMID: 34849880 PMCID: PMC8633083 DOI: 10.1093/genetics/iyab119] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/10/2021] [Indexed: 11/14/2022] Open
Abstract
Current methods of identifying positively selected regions in the genome are limited in two key ways: the underlying models cannot account for the timing of adaptive events and the comparison between models of selective sweeps and sequence data is generally made via simple summaries of genetic diversity. Here, we develop a tractable method of describing the effect of positive selection on the genealogical histories in the surrounding genome, explicitly modeling both the timing and context of an adaptive event. In addition, our framework allows us to go beyond analyzing polymorphism data via the site frequency spectrum or summaries thereof and instead leverage information contained in patterns of linked variants. Tests on both simulations and a human data example, as well as a comparison to SweepFinder2, show that even with very small sample sizes, our analytic framework has higher power to identify old selective sweeps and to correctly infer both the time and strength of selection. Finally, we derived the marginal distribution of genealogical branch lengths at a locus affected by selection acting at a linked site. This provides a much-needed link between our analytic understanding of the effects of sweeps on sequence variation and recent advances in simulation and heuristic inference procedures that allow researchers to examine the sequence of genealogical histories along the genome.
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Affiliation(s)
- Gertjan Bisschop
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Konrad Lohse
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Derek Setter
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh EH9 3FL, UK
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47
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Calfee E, Gates D, Lorant A, Perkins MT, Coop G, Ross-Ibarra J. Selective sorting of ancestral introgression in maize and teosinte along an elevational cline. PLoS Genet 2021; 17:e1009810. [PMID: 34634032 PMCID: PMC8530355 DOI: 10.1371/journal.pgen.1009810] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/21/2021] [Accepted: 09/07/2021] [Indexed: 12/02/2022] Open
Abstract
While often deleterious, hybridization can also be a key source of genetic variation and pre-adapted haplotypes, enabling rapid evolution and niche expansion. Here we evaluate these opposing selection forces on introgressed ancestry between maize (Zea mays ssp. mays) and its wild teosinte relative, mexicana (Zea mays ssp. mexicana). Introgression from ecologically diverse teosinte may have facilitated maize's global range expansion, in particular to challenging high elevation regions (> 1500 m). We generated low-coverage genome sequencing data for 348 maize and mexicana individuals to evaluate patterns of introgression in 14 sympatric population pairs, spanning the elevational range of mexicana, a teosinte endemic to the mountains of Mexico. While recent hybrids are commonly observed in sympatric populations and mexicana demonstrates fine-scale local adaptation, we find that the majority of mexicana ancestry tracts introgressed into maize over 1000 generations ago. This mexicana ancestry seems to have maintained much of its diversity and likely came from a common ancestral source, rather than contemporary sympatric populations, resulting in relatively low FST between mexicana ancestry tracts sampled from geographically distant maize populations. Introgressed mexicana ancestry in maize is reduced in lower-recombination rate quintiles of the genome and around domestication genes, consistent with pervasive selection against introgression. However, we also find mexicana ancestry increases across the sampled elevational gradient and that high introgression peaks are most commonly shared among high-elevation maize populations, consistent with introgression from mexicana facilitating adaptation to the highland environment. In the other direction, we find patterns consistent with adaptive and clinal introgression of maize ancestry into sympatric mexicana at many loci across the genome, suggesting that maize also contributes to adaptation in mexicana, especially at the lower end of its elevational range. In sympatric maize, in addition to high introgression regions we find many genomic regions where selection for local adaptation maintains steep gradients in introgressed mexicana ancestry across elevation, including at least two inversions: the well-characterized 14 Mb Inv4m on chromosome 4 and a novel 3 Mb inversion Inv9f surrounding the macrohairless1 locus on chromosome 9. Most outlier loci with high mexicana introgression show no signals of sweeps or local sourcing from sympatric populations and so likely represent ancestral introgression sorted by selection, resulting in correlated but distinct outcomes of introgression in different contemporary maize populations.
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Affiliation(s)
- Erin Calfee
- Center for Population Biology, University of California, Davis, California, United States of America
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Daniel Gates
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Anne Lorant
- Department of Plant Sciences, University of California, Davis, California, United States of America
| | - M. Taylor Perkins
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Graham Coop
- Center for Population Biology, University of California, Davis, California, United States of America
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
| | - Jeffrey Ross-Ibarra
- Center for Population Biology, University of California, Davis, California, United States of America
- Department of Evolution and Ecology, University of California, Davis, California, United States of America
- Genome Center, University of California, Davis, California, United States of America
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48
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Findley AS, Zhang X, Boye C, Lin YL, Kalita CA, Barreiro L, Lohmueller KE, Pique-Regi R, Luca F. A signature of Neanderthal introgression on molecular mechanisms of environmental responses. PLoS Genet 2021; 17:e1009493. [PMID: 34570765 PMCID: PMC8509894 DOI: 10.1371/journal.pgen.1009493] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 10/12/2021] [Accepted: 08/18/2021] [Indexed: 12/17/2022] Open
Abstract
Ancient human migrations led to the settlement of population groups in varied environmental contexts worldwide. The extent to which adaptation to local environments has shaped human genetic diversity is a longstanding question in human evolution. Recent studies have suggested that introgression of archaic alleles in the genome of modern humans may have contributed to adaptation to environmental pressures such as pathogen exposure. Functional genomic studies have demonstrated that variation in gene expression across individuals and in response to environmental perturbations is a main mechanism underlying complex trait variation. We considered gene expression response to in vitro treatments as a molecular phenotype to identify genes and regulatory variants that may have played an important role in adaptations to local environments. We investigated if Neanderthal introgression in the human genome may contribute to the transcriptional response to environmental perturbations. To this end we used eQTLs for genes differentially expressed in a panel of 52 cellular environments, resulting from 5 cell types and 26 treatments, including hormones, vitamins, drugs, and environmental contaminants. We found that SNPs with introgressed Neanderthal alleles (N-SNPs) disrupt binding of transcription factors important for environmental responses, including ionizing radiation and hypoxia, and for glucose metabolism. We identified an enrichment for N-SNPs among eQTLs for genes differentially expressed in response to 8 treatments, including glucocorticoids, caffeine, and vitamin D. Using Massively Parallel Reporter Assays (MPRA) data, we validated the regulatory function of 21 introgressed Neanderthal variants in the human genome, corresponding to 8 eQTLs regulating 15 genes that respond to environmental perturbations. These findings expand the set of environments where archaic introgression may have contributed to adaptations to local environments in modern humans and provide experimental validation for the regulatory function of introgressed variants.
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Affiliation(s)
- Anthony S. Findley
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
| | - Xinjun Zhang
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, California, United States of America
| | - Carly Boye
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
| | - Yen Lung Lin
- Genetics Section, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Cynthia A. Kalita
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
| | - Luis Barreiro
- Genetics Section, Department of Medicine, University of Chicago, Chicago, Illinois, United States of America
| | - Kirk E. Lohmueller
- Department of Ecology and Evolutionary Biology, UCLA, Los Angeles, California, United States of America
- Department of Human Genetics, David Geffen School of Medicine, UCLA, Los Angeles, California, United States of America
| | - Roger Pique-Regi
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, United States of America
| | - Francesca Luca
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, United States of America
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49
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Ferrer Obiol J, James HF, Chesser RT, Bretagnolle V, González-Solís J, Rozas J, Riutort M, Welch AJ. Integrating Sequence Capture and Restriction Site-Associated DNA Sequencing to Resolve Recent Radiations of Pelagic Seabirds. Syst Biol 2021; 70:976-996. [PMID: 33512506 PMCID: PMC8357341 DOI: 10.1093/sysbio/syaa101] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 11/13/2020] [Accepted: 12/15/2020] [Indexed: 01/01/2023] Open
Abstract
The diversification of modern birds has been shaped by a number of radiations. Rapid diversification events make reconstructing the evolutionary relationships among taxa challenging due to the convoluted effects of incomplete lineage sorting (ILS) and introgression. Phylogenomic data sets have the potential to detect patterns of phylogenetic incongruence, and to address their causes. However, the footprints of ILS and introgression on sequence data can vary between different phylogenomic markers at different phylogenetic scales depending on factors such as their evolutionary rates or their selection pressures. We show that combining phylogenomic markers that evolve at different rates, such as paired-end double-digest restriction site-associated DNA (PE-ddRAD) and ultraconserved elements (UCEs), allows a comprehensive exploration of the causes of phylogenetic discordance associated with short internodes at different timescales. We used thousands of UCE and PE-ddRAD markers to produce the first well-resolved phylogeny of shearwaters, a group of medium-sized pelagic seabirds that are among the most phylogenetically controversial and endangered bird groups. We found that phylogenomic conflict was mainly derived from high levels of ILS due to rapid speciation events. We also documented a case of introgression, despite the high philopatry of shearwaters to their breeding sites, which typically limits gene flow. We integrated state-of-the-art concatenated and coalescent-based approaches to expand on previous comparisons of UCE and RAD-Seq data sets for phylogenetics, divergence time estimation, and inference of introgression, and we propose a strategy to optimize RAD-Seq data for phylogenetic analyses. Our results highlight the usefulness of combining phylogenomic markers evolving at different rates to understand the causes of phylogenetic discordance at different timescales. [Aves; incomplete lineage sorting; introgression; PE-ddRAD-Seq; phylogenomics; radiations; shearwaters; UCEs.].
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Affiliation(s)
- Joan Ferrer Obiol
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Catalonia, Spain
| | - Helen F James
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
| | - R Terry Chesser
- Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC, USA
- U.S. Geological Survey, Patuxent Wildlife Research Center, Laurel, MD, USA
| | - Vincent Bretagnolle
- Centre d’Études Biologiques de Chizé, CNRS & La Rochelle Université, 79360, Villiers en Bois, France
| | - Jacob González-Solís
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Catalonia, Spain
- Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Facultat de Biologia, Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Julio Rozas
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Catalonia, Spain
| | - Marta Riutort
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona, Barcelona, Catalonia, Spain
- Institut de Recerca de la Biodiversitat (IRBio), Barcelona, Catalonia, Spain
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50
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Moran BM, Payne C, Langdon Q, Powell DL, Brandvain Y, Schumer M. The genomic consequences of hybridization. eLife 2021; 10:e69016. [PMID: 34346866 PMCID: PMC8337078 DOI: 10.7554/elife.69016] [Citation(s) in RCA: 84] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/09/2021] [Indexed: 12/29/2022] Open
Abstract
In the past decade, advances in genome sequencing have allowed researchers to uncover the history of hybridization in diverse groups of species, including our own. Although the field has made impressive progress in documenting the extent of natural hybridization, both historical and recent, there are still many unanswered questions about its genetic and evolutionary consequences. Recent work has suggested that the outcomes of hybridization in the genome may be in part predictable, but many open questions about the nature of selection on hybrids and the biological variables that shape such selection have hampered progress in this area. We synthesize what is known about the mechanisms that drive changes in ancestry in the genome after hybridization, highlight major unresolved questions, and discuss their implications for the predictability of genome evolution after hybridization.
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Affiliation(s)
- Benjamin M Moran
- Department of Biology, Stanford UniversityStanfordUnited States
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”HidalgoMexico
| | - Cheyenne Payne
- Department of Biology, Stanford UniversityStanfordUnited States
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”HidalgoMexico
| | - Quinn Langdon
- Department of Biology, Stanford UniversityStanfordUnited States
| | - Daniel L Powell
- Department of Biology, Stanford UniversityStanfordUnited States
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”HidalgoMexico
| | - Yaniv Brandvain
- Department of Ecology, Evolution & Behavior and Plant and Microbial Biology, University of MinnesotaMinneapolisUnited States
| | - Molly Schumer
- Department of Biology, Stanford UniversityStanfordUnited States
- Centro de Investigaciones Científicas de las Huastecas “Aguazarca”HidalgoMexico
- Hanna H. Gray Fellow, Howard Hughes Medical InstituteStanfordUnited States
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