51
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Zhang H, Fu Q, Shi X, Pan Z, Yang W, Huang Z, Tang T, He X, Zhang R. Human A-to-I RNA editing SNP loci are enriched in GWAS signals for autoimmune diseases and under balancing selection. Genome Biol 2020; 21:288. [PMID: 33256812 PMCID: PMC7702712 DOI: 10.1186/s13059-020-02205-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 11/16/2020] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Adenosine-to-inosine (A-to-I) RNA editing plays important roles in diversifying the transcriptome and preventing MDA5 sensing of endogenous dsRNA as nonself. To date, few studies have investigated the population genomic signatures of A-to-I editing due to the lack of editing sites overlapping with SNPs. RESULTS In this study, we applied a pipeline to robustly identify SNP editing sites from population transcriptomic data and combined functional genomics, GWAS, and population genomics approaches to study the function and evolution of A-to-I editing. We find that the G allele, which is equivalent to edited I, is overrepresented in editing SNPs. Functionally, A/G editing SNPs are highly enriched in GWAS signals of autoimmune and immune-related diseases. Evolutionarily, derived allele frequency distributions of A/G editing SNPs for both A and G alleles as the ancestral alleles are skewed toward intermediate frequency alleles relative to neutral SNPs, a hallmark of balancing selection, suggesting that both A and G alleles are functionally important. The signal of balancing selection is confirmed by a number of additional population genomic analyses. CONCLUSIONS We uncovered a hidden layer of A-to-I RNA editing SNP loci as a common target of balancing selection, and we propose that the maintenance of such editing SNP variations may be at least partially due to constraints on the resolution of the balance between immune activity and self-tolerance.
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Affiliation(s)
- Hui Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, People's Republic of China
| | - Qiang Fu
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xinrui Shi
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Ziqing Pan
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Wenbing Yang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Zichao Huang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Tian Tang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Xionglei He
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Rui Zhang
- Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou, People's Republic of China.
- RNA Biomedical Institute, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.
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52
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Cheng X, DeGiorgio M. Flexible Mixture Model Approaches That Accommodate Footprint Size Variability for Robust Detection of Balancing Selection. Mol Biol Evol 2020; 37:3267-3291. [PMID: 32462188 PMCID: PMC7820363 DOI: 10.1093/molbev/msaa134] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Long-term balancing selection typically leaves narrow footprints of increased genetic diversity, and therefore most detection approaches only achieve optimal performances when sufficiently small genomic regions (i.e., windows) are examined. Such methods are sensitive to window sizes and suffer substantial losses in power when windows are large. Here, we employ mixture models to construct a set of five composite likelihood ratio test statistics, which we collectively term B statistics. These statistics are agnostic to window sizes and can operate on diverse forms of input data. Through simulations, we show that they exhibit comparable power to the best-performing current methods, and retain substantially high power regardless of window sizes. They also display considerable robustness to high mutation rates and uneven recombination landscapes, as well as an array of other common confounding scenarios. Moreover, we applied a specific version of the B statistics, termed B2, to a human population-genomic data set and recovered many top candidates from prior studies, including the then-uncharacterized STPG2 and CCDC169-SOHLH2, both of which are related to gamete functions. We further applied B2 on a bonobo population-genomic data set. In addition to the MHC-DQ genes, we uncovered several novel candidate genes, such as KLRD1, involved in viral defense, and SCN9A, associated with pain perception. Finally, we show that our methods can be extended to account for multiallelic balancing selection and integrated the set of statistics into open-source software named BalLeRMix for future applications by the scientific community.
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Affiliation(s)
- Xiaoheng Cheng
- Huck Institutes of Life Sciences, Pennsylvania State University, University Park, PA
- Department of Biology, Pennsylvania State University, University Park, PA
| | - Michael DeGiorgio
- Department of Computer and Electrical Engineering and Computer Science, Florida Atlantic University, Boca Raton, FL
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53
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Fair BJ, Blake LE, Sarkar A, Pavlovic BJ, Cuevas C, Gilad Y. Gene expression variability in human and chimpanzee populations share common determinants. eLife 2020; 9:59929. [PMID: 33084571 PMCID: PMC7644215 DOI: 10.7554/elife.59929] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/20/2020] [Indexed: 12/20/2022] Open
Abstract
Inter-individual variation in gene expression has been shown to be heritable and is often associated with differences in disease susceptibility between individuals. Many studies focused on mapping associations between genetic and gene regulatory variation, yet much less attention has been paid to the evolutionary processes that shape the observed differences in gene regulation between individuals in humans or any other primate. To begin addressing this gap, we performed a comparative analysis of gene expression variability and expression quantitative trait loci (eQTLs) in humans and chimpanzees, using gene expression data from primary heart samples. We found that expression variability in both species is often determined by non-genetic sources, such as cell-type heterogeneity. However, we also provide evidence that inter-individual variation in gene regulation can be genetically controlled, and that the degree of such variability is generally conserved in humans and chimpanzees. In particular, we found a significant overlap of orthologous genes associated with eQTLs in both species. We conclude that gene expression variability in humans and chimpanzees often evolves under similar evolutionary pressures.
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Affiliation(s)
| | - Lauren E Blake
- Department of Human Genetics, University of Chicago, Chicago, United States
| | - Abhishek Sarkar
- Department of Human Genetics, University of Chicago, Chicago, United States
| | - Bryan J Pavlovic
- Department of Neurology, University of California, San Francisco (UCSF), San Francisco, United States
| | - Claudia Cuevas
- Department of Human Genetics, University of Chicago, Chicago, United States
| | - Yoav Gilad
- Department of Medicine, University of Chicago, Chicago, United States.,Department of Human Genetics, University of Chicago, Chicago, United States
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54
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Schrider DR. Background Selection Does Not Mimic the Patterns of Genetic Diversity Produced by Selective Sweeps. Genetics 2020; 216:499-519. [PMID: 32847814 PMCID: PMC7536861 DOI: 10.1534/genetics.120.303469] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 08/04/2020] [Indexed: 12/28/2022] Open
Abstract
It is increasingly evident that natural selection plays a prominent role in shaping patterns of diversity across the genome. The most commonly studied modes of natural selection are positive selection and negative selection, which refer to directional selection for and against derived mutations, respectively. Positive selection can result in hitchhiking events, in which a beneficial allele rapidly replaces all others in the population, creating a valley of diversity around the selected site along with characteristic skews in allele frequencies and linkage disequilibrium among linked neutral polymorphisms. Similarly, negative selection reduces variation not only at selected sites but also at linked sites, a phenomenon called background selection (BGS). Thus, discriminating between these two forces may be difficult, and one might expect efforts to detect hitchhiking to produce an excess of false positives in regions affected by BGS. Here, we examine the similarity between BGS and hitchhiking models via simulation. First, we show that BGS may somewhat resemble hitchhiking in simplistic scenarios in which a region constrained by negative selection is flanked by large stretches of unconstrained sites, echoing previous results. However, this scenario does not mirror the actual spatial arrangement of selected sites across the genome. By performing forward simulations under more realistic scenarios of BGS, modeling the locations of protein-coding and conserved noncoding DNA in real genomes, we show that the spatial patterns of variation produced by BGS rarely mimic those of hitchhiking events. Indeed, BGS is not substantially more likely than neutrality to produce false signatures of hitchhiking. This holds for simulations modeled after both humans and Drosophila, and for several different demographic histories. These results demonstrate that appropriately designed scans for hitchhiking need not consider BGS's impact on false-positive rates. However, we do find evidence that BGS increases the false-negative rate for hitchhiking, an observation that demands further investigation.
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Affiliation(s)
- Daniel R Schrider
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina 27514
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55
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Ruzicka F, Dutoit L, Czuppon P, Jordan CY, Li X, Olito C, Runemark A, Svensson EI, Yazdi HP, Connallon T. The search for sexually antagonistic genes: Practical insights from studies of local adaptation and statistical genomics. Evol Lett 2020; 4:398-415. [PMID: 33014417 PMCID: PMC7523564 DOI: 10.1002/evl3.192] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/13/2020] [Accepted: 07/28/2020] [Indexed: 12/16/2022] Open
Abstract
Sexually antagonistic (SA) genetic variation-in which alleles favored in one sex are disfavored in the other-is predicted to be common and has been documented in several animal and plant populations, yet we currently know little about its pervasiveness among species or its population genetic basis. Recent applications of genomics in studies of SA genetic variation have highlighted considerable methodological challenges to the identification and characterization of SA genes, raising questions about the feasibility of genomic approaches for inferring SA selection. The related fields of local adaptation and statistical genomics have previously dealt with similar challenges, and lessons from these disciplines can therefore help overcome current difficulties in applying genomics to study SA genetic variation. Here, we integrate theoretical and analytical concepts from local adaptation and statistical genomics research-including F ST and F IS statistics, genome-wide association studies, pedigree analyses, reciprocal transplant studies, and evolve-and-resequence experiments-to evaluate methods for identifying SA genes and genome-wide signals of SA genetic variation. We begin by developing theoretical models for between-sex F ST and F IS, including explicit null distributions for each statistic, and using them to critically evaluate putative multilocus signals of sex-specific selection in previously published datasets. We then highlight new statistics that address some of the limitations of F ST and F IS, along with applications of more direct approaches for characterizing SA genetic variation, which incorporate explicit fitness measurements. We finish by presenting practical guidelines for the validation and evolutionary analysis of candidate SA genes and discussing promising empirical systems for future work.
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Affiliation(s)
- Filip Ruzicka
- School of Biological SciencesMonash UniversityClaytonVIC 3800Australia
| | - Ludovic Dutoit
- Department of ZoologyUniversity of OtagoDunedin9054New Zealand
| | - Peter Czuppon
- Institute of Ecology and Environmental Sciences, UPEC, CNRS, IRD, INRASorbonne UniversitéParis75252France
- Center for Interdisciplinary Research in Biology, CNRS, Collège de FrancePSL Research UniversityParis75231France
| | - Crispin Y. Jordan
- School of Biomedical SciencesUniversity of EdinburghEdinburghEH8 9XDUnited Kingdom
| | - Xiang‐Yi Li
- Institute of BiologyUniversity of NeuchâtelNeuchatelCH‐2000Switzerland
| | - Colin Olito
- Department of BiologyLund UniversityLundSE‐22362Sweden
| | - Anna Runemark
- Department of BiologyLund UniversityLundSE‐22362Sweden
| | | | | | - Tim Connallon
- School of Biological SciencesMonash UniversityClaytonVIC 3800Australia
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56
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Ebert D, Fields PD. Host-parasite co-evolution and its genomic signature. Nat Rev Genet 2020; 21:754-768. [PMID: 32860017 DOI: 10.1038/s41576-020-0269-1] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2020] [Indexed: 01/14/2023]
Abstract
Studies in diverse biological systems have indicated that host-parasite co-evolution is responsible for the extraordinary genetic diversity seen in some genomic regions, such as major histocompatibility (MHC) genes in jawed vertebrates and resistance genes in plants. This diversity is believed to evolve under balancing selection on hosts by parasites. However, the mechanisms that link the genomic signatures in these regions to the underlying co-evolutionary process are only slowly emerging. We still lack a clear picture of the co-evolutionary concepts and of the genetic basis of the co-evolving phenotypic traits in the interacting antagonists. Emerging genomic tools that provide new options for identifying underlying genes will contribute to a fuller understanding of the co-evolutionary process.
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Affiliation(s)
- Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland. .,Wissenschaftskolleg zu Berlin, Berlin, Germany.
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel, Switzerland
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57
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Truong L, Matern BM, Groeneweg M, D'Orsogna L, Martinez P, Tilanus MGJ, De Santis D. Polymorphism clustering of the 21.5 kb DPA-promoter-DPB region reveals novel extended full-length haplotypes. HLA 2020; 96:299-311. [PMID: 32536006 DOI: 10.1111/tan.13975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 06/02/2020] [Accepted: 06/08/2020] [Indexed: 01/12/2023]
Abstract
DPB1 and DPA1 genes share the same promoter region. Single-nucleotide polymorphisms (SNPs) within the regulatory regions of DP have been reported. This study hypothesizes that by including the SNPs in the promoter region of DP, extended haplotypes are defined, and promoter polymorphism is more extensive than what is currently reported. To identify the SNPs in the region of interest, the DP region spanning 21.5 kb was amplified in three separate long-ranged polymerase chain reactions. A DNA panel consisting of 100 samples was selected to represent a broad range of DPB1 alleles. The panel was amplified and sequenced using a dual sequencing strategy. Binary alignment map (BAM) alignments were generated and the mapped sequence alignments were analyzed using Integrative Genomics Viewer. A total of 76 SNPs were identified, and SNPs were clustered into 12 SNP-linked haplotypes. Multiple sequence alignments of promoter sequences indicated four distinct lineages within the connective region (CR) between two genes. The relationship between DPA1, CR, DPB1, and amino acid motifs was found to be correlated with HV1 and HV6. Of the 12 promoter haplotypes, DPB1 alleles observed with ProDP-4 were in complete linkage with HV1/2/5/6, the rs9277534G SNP, and the highly immunogenic T-cell epitope group. Multiple extended haplotypes of different intronic subtypes of the same DPB1 alleles were also identified. This new view of the full DP haplotype shows the relation of polymorphism, genes, and alleles, and provides a basis for future functionality related nomenclature. The novel clustering of the DP-extended haplotype warrants future investigations of DP haplotype matching in the outcome of haematopoietic stem cell transplantation (HSCT).
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Affiliation(s)
- Linh Truong
- Department of Clinical Immunology, PathWest, Fiona Stanley Hospital, Perth, Western Australia, Australia.,School of Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Ben M Matern
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Mathijs Groeneweg
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Lloyd D'Orsogna
- Department of Clinical Immunology, PathWest, Fiona Stanley Hospital, Perth, Western Australia, Australia.,School of Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Patricia Martinez
- Department of Clinical Immunology, PathWest, Fiona Stanley Hospital, Perth, Western Australia, Australia.,School of Medicine, The University of Western Australia, Perth, Western Australia, Australia
| | - Marcel G J Tilanus
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Dianne De Santis
- Department of Clinical Immunology, PathWest, Fiona Stanley Hospital, Perth, Western Australia, Australia.,School of Medicine, The University of Western Australia, Perth, Western Australia, Australia
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58
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Barquera R, Collen E, Di D, Buhler S, Teixeira J, Llamas B, Nunes JM, Sanchez-Mazas A. Binding affinities of 438 HLA proteins to complete proteomes of seven pandemic viruses and distributions of strongest and weakest HLA peptide binders in populations worldwide. HLA 2020; 96:277-298. [PMID: 32475052 PMCID: PMC7300650 DOI: 10.1111/tan.13956] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 12/11/2022]
Abstract
We report detailed peptide‐binding affinities between 438 HLA Class I and Class II proteins and complete proteomes of seven pandemic human viruses, including coronaviruses, influenza viruses and HIV‐1. We contrast these affinities with HLA allele frequencies across hundreds of human populations worldwide. Statistical modelling shows that peptide‐binding affinities classified into four distinct categories depend on the HLA locus but that the type of virus is only a weak predictor, except in the case of HIV‐1. Among the strong HLA binders (IC50 ≤ 50), we uncovered 16 alleles (the top ones being A*02:02, B*15:03 and DRB1*01:02) binding more than 1% of peptides derived from all viruses, 9 (top ones including HLA‐A*68:01, B*15:25, C*03:02 and DRB1*07:01) binding all viruses except HIV‐1, and 15 (top ones A*02:01 and C*14:02) only binding coronaviruses. The frequencies of strongest and weakest HLA peptide binders differ significantly among populations from different geographic regions. In particular, Indigenous peoples of America show both higher frequencies of strongest and lower frequencies of weakest HLA binders. As many HLA proteins are found to be strong binders of peptides derived from distinct viral families, and are hence promiscuous (or generalist), we discuss this result in relation to possible signatures of natural selection on HLA promiscuous alleles due to past pathogenic infections. Our findings are highly relevant for both evolutionary genetics and the development of vaccine therapies. However they should not lead to forget that individual resistance and vulnerability to diseases go beyond the sole HLA allelic affinity and depend on multiple, complex and often unknown biological, environmental and other variables.
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Affiliation(s)
- Rodrigo Barquera
- Department of Archaeogenetics, Max Planck Institute for the Science of Human History, Jena, Germany
| | - Evelyn Collen
- Australian Centre for Ancient DNA (ACAD), Department of Genetics and Evolution, The University of Adelaide, Adelaide, South Australia, Australia
| | - Da Di
- Anthropology Unit, Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland
| | - Stéphane Buhler
- Anthropology Unit, Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland.,Transplantation Immunology Unit and National Reference Laboratory for Histocompatibility, Department of Diagnostic, Geneva University Hospitals, Geneva, Switzerland
| | - João Teixeira
- Australian Centre for Ancient DNA (ACAD), Department of Genetics and Evolution, The University of Adelaide, Adelaide, South Australia, Australia.,School of Biological Sciences, Centre of Excellence for Australian Biodiversity and Heritage, The University of Adelaide, Adelaide, South Australia, Australia
| | - Bastien Llamas
- School of Biological Sciences, Centre of Excellence for Australian Biodiversity and Heritage, The University of Adelaide, Adelaide, South Australia, Australia.,The Environment Institute, The University of Adelaide, Adelaide, South Australia, Australia
| | - José M Nunes
- Anthropology Unit, Department of Genetics and Evolution, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva (IGE3), University of Geneva, Geneva, Switzerland
| | - Alicia Sanchez-Mazas
- Anthropology Unit, 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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59
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Abstract
Malaria has been the pre-eminent cause of early mortality in many parts of the world throughout much of the last five thousand years and, as a result, it is the strongest force for selective pressure on the human genome yet described. Around one third of the variability in the risk of severe and complicated malaria is now explained by additive host genetic effects. Many individual variants have been identified that are associated with malaria protection, but the most important all relate to the structure or function of red blood cells. They include the classical polymorphisms that cause sickle cell trait, α-thalassaemia, G6PD deficiency, and the major red cell blood group variants. More recently however, with improving technology and experimental design, others have been identified that include the Dantu blood group variant, polymorphisms in the red cell membrane protein ATP2B4, and several variants related to the immune response. Characterising how these genes confer their effects could eventually inform novel therapeutic approaches to combat malaria. Nevertheless, all together, only a small proportion of the heritable component of malaria resistance can be explained by the variants described so far, underscoring its complex genetic architecture and the need for continued research.
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Affiliation(s)
- Silvia N Kariuki
- Department of Epidemiology, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
| | - Thomas N Williams
- Department of Epidemiology, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Department of Medicine, Imperial College of Science and Technology, London, UK.
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60
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Barreiro LB, Quintana-Murci L. Evolutionary and population (epi)genetics of immunity to infection. Hum Genet 2020; 139:723-732. [PMID: 32285198 PMCID: PMC7285878 DOI: 10.1007/s00439-020-02167-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/07/2020] [Indexed: 12/29/2022]
Abstract
Immune response is one of the functions that have been more strongly targeted by natural selection during human evolution. The evolutionary genetic dissection of the immune system has greatly helped to distinguish genes and functions that are essential, redundant or advantageous for human survival. It is also becoming increasingly clear that admixture between early Eurasians with now-extinct hominins such as Neanderthals or Denisovans, or admixture between modern human populations, can be beneficial for human adaptation to pathogen pressures. In this review, we discuss how the integration of population genetics with functional genomics in diverse human populations can inform about the changes in immune functions related to major lifestyle transitions (e.g., from hunting and gathering to farming), the action of natural selection to the evolution of the immune system, and the history of past epidemics. We also highlight the need of expanding the characterization of the immune system to a larger array of human populations-particularly neglected human groups historically exposed to different pathogen pressures-to fully capture the relative contribution of genetic, epigenetic, and environmental factors to immune response variation in humans.
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Affiliation(s)
- Luis B Barreiro
- Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, IL, 60637, USA.
| | - Lluis Quintana-Murci
- Unit of Human Evolutionary Genetics, CNRS UMR2000, Institut Pasteur, 75015, Paris, France
- Collège de France, 75005, Paris, France
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61
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Matern BM, Olieslagers TI, Groeneweg M, Duygu B, Wieten L, Tilanus MGJ, Voorter CEM. Long-Read Nanopore Sequencing Validated for Human Leukocyte Antigen Class I Typing in Routine Diagnostics. J Mol Diagn 2020; 22:912-919. [PMID: 32302780 DOI: 10.1016/j.jmoldx.2020.04.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 03/03/2020] [Accepted: 04/02/2020] [Indexed: 01/23/2023] Open
Abstract
Matching of human leukocyte antigen (HLA) gene polymorphisms by high-resolution DNA sequence analysis is the gold standard for determining compatibility between patient and donor for hematopoietic stem cell transplantation. Single-molecule sequencing (PacBio or MinION) is a newest (third) generation sequencing approach. MinION is a nanopore sequencing platform, which provides long targeted DNA sequences. The long reads provide unambiguous phasing, but the initial high error profile prevented its use in high-impact applications, such as HLA typing for HLA matching of donor and recipient in the transplantation setting. Ongoing developments on instrumentation and basecalling software have improved the per-base accuracy of 1D2 nanopore reads tremendously. In the current study, two validation panels of samples covering 70 of the 71 known HLA class I allele groups were used to compare third field sequences obtained by MinION, with Sanger sequence-based typing showing a 100% concordance between both data sets. In addition, the first validation panel was used to set the acceptance criteria for the use of MinION in a routine setting. The acceptance criteria were subsequently confirmed with the second validation panel. In summary, the present study describes validation and implementation of nanopore sequencing HLA class I typing method and illustrates that nanopore sequencing technology has advanced to a point where it can be used in routine diagnostics with high accuracy.
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Affiliation(s)
- Benedict M Matern
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Timo I Olieslagers
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Mathijs Groeneweg
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Burcu Duygu
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Lotte Wieten
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Marcel G J Tilanus
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Christina E M Voorter
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands.
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62
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Dehasque M, Ávila‐Arcos MC, Díez‐del‐Molino D, Fumagalli M, Guschanski K, Lorenzen ED, Malaspinas A, Marques‐Bonet T, Martin MD, Murray GGR, Papadopulos AST, Therkildsen NO, Wegmann D, Dalén L, Foote AD. Inference of natural selection from ancient DNA. Evol Lett 2020; 4:94-108. [PMID: 32313686 PMCID: PMC7156104 DOI: 10.1002/evl3.165] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 01/13/2020] [Accepted: 02/02/2020] [Indexed: 01/01/2023] Open
Abstract
Evolutionary processes, including selection, can be indirectly inferred based on patterns of genomic variation among contemporary populations or species. However, this often requires unrealistic assumptions of ancestral demography and selective regimes. Sequencing ancient DNA from temporally spaced samples can inform about past selection processes, as time series data allow direct quantification of population parameters collected before, during, and after genetic changes driven by selection. In this Comment and Opinion, we advocate for the inclusion of temporal sampling and the generation of paleogenomic datasets in evolutionary biology, and highlight some of the recent advances that have yet to be broadly applied by evolutionary biologists. In doing so, we consider the expected signatures of balancing, purifying, and positive selection in time series data, and detail how this can advance our understanding of the chronology and tempo of genomic change driven by selection. However, we also recognize the limitations of such data, which can suffer from postmortem damage, fragmentation, low coverage, and typically low sample size. We therefore highlight the many assumptions and considerations associated with analyzing paleogenomic data and the assumptions associated with analytical methods.
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Affiliation(s)
- Marianne Dehasque
- Centre for Palaeogenetics10691StockholmSweden
- Department of Bioinformatics and GeneticsSwedish Museum of Natural History10405StockholmSweden
- Department of ZoologyStockholm University10691StockholmSweden
| | - María C. Ávila‐Arcos
- International Laboratory for Human Genome Research (LIIGH)UNAM JuriquillaQueretaro76230Mexico
| | - David Díez‐del‐Molino
- Centre for Palaeogenetics10691StockholmSweden
- Department of ZoologyStockholm University10691StockholmSweden
| | - Matteo Fumagalli
- Department of Life Sciences, Silwood Park CampusImperial College LondonAscotSL5 7PYUnited Kingdom
| | - Katerina Guschanski
- Animal Ecology, Department of Ecology and Genetics, Science for Life LaboratoryUppsala University75236UppsalaSweden
| | | | - Anna‐Sapfo Malaspinas
- Department of Computational BiologyUniversity of Lausanne1015LausanneSwitzerland
- SIB Swiss Institute of Bioinformatics1015LausanneSwitzerland
| | - Tomas Marques‐Bonet
- Institut de Biologia Evolutiva(CSIC‐Universitat Pompeu Fabra), Parc de Recerca Biomèdica de BarcelonaBarcelonaSpain
- National Centre for Genomic Analysis—Centre for Genomic RegulationBarcelona Institute of Science and Technology08028BarcelonaSpain
- Institucio Catalana de Recerca i Estudis Avançats08010BarcelonaSpain
- Institut Català de Paleontologia Miquel CrusafontUniversitat Autònoma de BarcelonaCerdanyola del VallèsSpain
| | - Michael D. Martin
- Department of Natural History, NTNU University MuseumNorwegian University of Science and Technology (NTNU)TrondheimNorway
| | - Gemma G. R. Murray
- Department of Veterinary MedicineUniversity of CambridgeCambridgeCB2 1TNUnited Kingdom
| | - Alexander S. T. Papadopulos
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological SciencesBangor UniversityBangorLL57 2UWUnited Kingdom
| | | | - Daniel Wegmann
- Department of BiologyUniversité de Fribourg1700FribourgSwitzerland
- Swiss Institute of BioinformaticsFribourgSwitzerland
| | - Love Dalén
- Centre for Palaeogenetics10691StockholmSweden
- Department of Bioinformatics and GeneticsSwedish Museum of Natural History10405StockholmSweden
| | - Andrew D. Foote
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological SciencesBangor UniversityBangorLL57 2UWUnited Kingdom
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63
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O’Neill MB, Laval G, Teixeira JC, Palmenberg AC, Pepperell CS. Genetic susceptibility to severe childhood asthma and rhinovirus-C maintained by balancing selection in humans for 150 000 years. Hum Mol Genet 2020; 29:736-744. [PMID: 31841129 PMCID: PMC7104676 DOI: 10.1093/hmg/ddz304] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/07/2019] [Accepted: 12/12/2019] [Indexed: 12/18/2022] Open
Abstract
Selective pressures imposed by pathogens have varied among human populations throughout their evolution, leading to marked inter-population differences at some genes mediating susceptibility to infectious and immune-related diseases. Here, we investigated the evolutionary history of a common polymorphism resulting in a Y529 versus C529 change in the cadherin related family member 3 (CDHR3) receptor which underlies variable susceptibility to rhinovirus-C infection and is associated with severe childhood asthma. The protective variant is the derived allele and is found at high frequency worldwide (69-95%). We detected genome-wide significant signatures of natural selection consistent with a rapid increase of the haplotypes carrying the allele, suggesting that non-neutral processes have acted on this locus across all human populations. However, the allele has not fixed in any population despite multiple lines of evidence suggesting that the mutation predates human migrations out of Africa. Using an approximate Bayesian computation method, we estimate the age of the mutation while explicitly accounting for past demography and positive or frequency-dependent balancing selection. Our analyses indicate a single emergence of the mutation in anatomically modern humans ~150 000 years ago and indicate that balancing selection has maintained the beneficial allele at high equilibrium frequencies worldwide. Apart from the well-known cases of the MHC and ABO genes, this study provides the first evidence that negative frequency-dependent selection plausibly acted on a human disease susceptibility locus, a form of balancing selection compatible with typical transmission dynamics of communicable respiratory viruses that might exploit CDHR3.
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Affiliation(s)
- Mary B O’Neill
- Department of Laboratory of Genetics, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Human Evolutionary Genetics Unit, Institut Pasteur, CNRS UMR2000, Paris 75015, France
| | - Guillaume Laval
- Department of Human Evolutionary Genetics Unit, Institut Pasteur, CNRS UMR2000, Paris 75015, France
| | - João C Teixeira
- Department of Human Evolutionary Genetics Unit, Institut Pasteur, CNRS UMR2000, Paris 75015, France
- Department of Australian Centre for Ancient DNA, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - Ann C Palmenberg
- Department of Biochemistry, Institute for Molecular Virology, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Caitlin S Pepperell
- Department of Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin—Madison, Madison, WI 53706, USA
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64
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Van Cleve J. Building a synthetic basis for kin selection and evolutionary game theory using population genetics. Theor Popul Biol 2020; 133:65-70. [PMID: 32165158 DOI: 10.1016/j.tpb.2020.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 03/02/2020] [Accepted: 03/04/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Jeremy Van Cleve
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA.
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65
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Wang M, Zhang L, Zhang Z, Li M, Wang D, Zhang X, Xi Z, Keefover-Ring K, Smart LB, DiFazio SP, Olson MS, Yin T, Liu J, Ma T. Phylogenomics of the genus Populus reveals extensive interspecific gene flow and balancing selection. THE NEW PHYTOLOGIST 2020; 225:1370-1382. [PMID: 31550399 DOI: 10.1111/nph.16215] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 09/16/2019] [Indexed: 05/10/2023]
Abstract
Phylogenetic analysis is complicated by interspecific gene flow and the presence of shared ancestral polymorphisms, particularly those maintained by balancing selection. In this study, we aimed to examine the prevalence of these factors during the diversification of Populus, a model tree genus in the Northern Hemisphere. We constructed phylogenetic trees of 29 Populus taxa using 80 individuals based on re-sequenced genomes. Our species tree analyses recovered four main clades in the genus based on consensus nuclear phylogenies, but in conflict with the plastome phylogeny. A few interspecific relationships remained unresolved within the multiple-species clade because of inconsistent gene trees. Our results indicated that gene flow has been widespread within each clade and also occurred among the four clades during their early divergence. We identified 45 candidate genes with ancient polymorphisms maintained by balancing selection. These genes were mainly associated with mating compatibility, growth and stress resistance. Both gene flow and selection-mediated ancient polymorphisms are prevalent in the genus Populus. These are potentially important contributors to adaptive variation. Our results provide a framework for the diversification of model tree genus that will facilitate future comparative studies.
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Affiliation(s)
- Mingcheng Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Lei Zhang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Zhiyang Zhang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Mengmeng Li
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Deyan Wang
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Xu Zhang
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & College of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Zhenxiang Xi
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
| | - Ken Keefover-Ring
- Departments of Botany and Geography, University of Wisconsin-Madison, 430 Lincoln Dr., Madison, WI, 53706, USA
| | - Lawrence B Smart
- Horticulture Section, School of Integrative Plant Science, New York State Agricultural Experiment Station, Cornell University, Geneva, NY, 14456, USA
| | - Stephen P DiFazio
- Department of Biology, West Virginia University, Morgantown, WV, 25606, USA
| | - Matthew S Olson
- Department of Biological Sciences, Texas Tech University, Box 43131, Lubbock, TX, 79409-3131, USA
| | - Tongming Yin
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing, 210037, China
| | - Jianquan Liu
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
- State Key Laboratory of Grassland Agro-Ecosystem, Institute of Innovation Ecology & College of Life Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Tao Ma
- Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, 610065, China
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66
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Maintenance of diversity in a hierarchical host–parasite model with balancing selection and reinfection. Stoch Process Their Appl 2020. [DOI: 10.1016/j.spa.2019.04.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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67
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Insights into malaria susceptibility using genome-wide data on 17,000 individuals from Africa, Asia and Oceania. Nat Commun 2019; 10:5732. [PMID: 31844061 PMCID: PMC6914791 DOI: 10.1038/s41467-019-13480-z] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 11/11/2019] [Indexed: 12/31/2022] Open
Abstract
The human genetic factors that affect resistance to infectious disease are poorly understood. Here we report a genome-wide association study in 17,000 severe malaria cases and population controls from 11 countries, informed by sequencing of family trios and by direct typing of candidate loci in an additional 15,000 samples. We identify five replicable associations with genome-wide levels of evidence including a newly implicated variant on chromosome 6. Jointly, these variants account for around one-tenth of the heritability of severe malaria, which we estimate as ~23% using genome-wide genotypes. We interrogate available functional data and discover an erythroid-specific transcription start site underlying the known association in ATP2B4, but are unable to identify a likely causal mechanism at the chromosome 6 locus. Previously reported HLA associations do not replicate in these samples. This large dataset will provide a foundation for further research on the genetic determinants of malaria resistance in diverse populations. Four genome-wide associated loci are currently known for malaria susceptibility. Here, the authors expand on earlier work by combining data from 11 malaria-endemic countries and additional population sequencing informing an African-enriched imputation reference panel, with findings including a previously unreported association on chromosome 6.
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68
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Matern BM, Olieslagers TI, Voorter CEM, Groeneweg M, Tilanus MGJ. Insights into the polymorphism in HLA-DRA and its evolutionary relationship with HLA haplotypes. HLA 2019; 95:117-127. [PMID: 31617688 DOI: 10.1111/tan.13730] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/07/2019] [Accepted: 10/12/2019] [Indexed: 01/05/2023]
Abstract
HLA-DRA encodes the alpha chain of the HLA-DR protein, one of the classical HLA class II molecules. Reported polymorphism within HLA-DRA is currently limited compared with other HLA genes, as only a single polymorphism encodes an amino acid difference in the translated protein. Since this SNP (rs7192, HLA00662.1:g.4276G>T p.Val217Leu) lies within exon 4, in the region encoding the cytoplasmic tail, the resulting protein is effectively monomorphic. For this reason, in-depth studies on HLA-DRA and its function have been limited. However, analysis of sequences from the 1000 Genomes Project and preliminary data from our lab reveals unrepresented polymorphism within HLA-DRA, suggesting a more complex role within the MHC than previously assumed. This study focuses on elucidating the extent of HLA-DRA polymorphism, and extending our understanding of the gene's role in HLA-DR~HLA-DQ haplotypes. Ninety-eight samples were sequenced for full-length HLA-DRA, and from this analysis, we identified 20 novel SNP positions in the intronic sequences within the 5711 bp region represented in IPD-IMGT/HLA. This polymorphism gives rise to at least 22 novel HLA-DRA alleles, and the patterns of intronic and 3' UTR polymorphism correspond to HLA-DRA~HLA-DRB345~HLA-DRB1~HLA-DQB1 haplotypes. The current understanding of the organization of the genes within the HLA-DR region assumes a single lineage for the HLA-DRA gene, as opposed to multiple gene lineages, such as in HLA-DRB. This study suggests that the intron and 3' UTR polymorphism of HLA-DRA indicates different lineages, and represents the HLA-DRA~HLA-DRB345~HLA-DRB1~HLA-DQB1 haplotypes.
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Affiliation(s)
- Ben M Matern
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Timo I Olieslagers
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Christina E M Voorter
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Mathijs Groeneweg
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Marcel G J Tilanus
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
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69
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Gatesy J, Sloan DB, Warren JM, Baker RH, Simmons MP, Springer MS. Partitioned coalescence support reveals biases in species-tree methods and detects gene trees that determine phylogenomic conflicts. Mol Phylogenet Evol 2019; 139:106539. [DOI: 10.1016/j.ympev.2019.106539] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 06/10/2019] [Accepted: 06/17/2019] [Indexed: 12/26/2022]
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70
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Gupta MK, Vadde R. Genetic Basis of Adaptation and Maladaptation via Balancing Selection. ZOOLOGY 2019; 136:125693. [PMID: 31513936 DOI: 10.1016/j.zool.2019.125693] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/03/2019] [Indexed: 10/26/2022]
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71
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An Evolutionary Perspective on the Impact of Genomic Copy Number Variation on Human Health. J Mol Evol 2019; 88:104-119. [PMID: 31522275 DOI: 10.1007/s00239-019-09911-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Accepted: 08/27/2019] [Indexed: 02/06/2023]
Abstract
Copy number variants (CNVs), deletions and duplications of segments of DNA, account for at least five times more variable base pairs in humans than single-nucleotide variants. Several common CNVs were shown to change coding and regulatory sequences and thus dramatically affect adaptive phenotypes involving immunity, perception, metabolism, skin structure, among others. Some of these CNVs were also associated with susceptibility to cancer, infection, and metabolic disorders. These observations raise the possibility that CNVs are a primary contributor to human phenotypic variation and consequently evolve under selective pressures. Indeed, locus-specific haplotype-level analyses revealed signatures of natural selection on several CNVs. However, more traditional tests of selection which are often applied to single-nucleotide variation often have diminished statistical power when applied to CNVs because they often do not show strong linkage disequilibrium with nearby variants. Recombination-based formation mechanisms of CNVs lead to frequent recurrence and gene conversion events, breaking the linkage disequilibrium involving CNVs. Similar methodological challenges also prevent routine genome-wide association studies to adequately investigate the impact of CNVs on heritable human disease. Thus, we argue that the full relevance of CNVs to human health and evolution is yet to be elucidated. We further argue that a holistic investigation of formation mechanisms within an evolutionary framework would provide a powerful framework to understand the functional and biomedical impact of CNVs. In this paper, we review several cases where studies reveal diverse evolutionary histories and unexpected functional consequences of CNVs. We hope that this review will encourage further work on CNVs by both evolutionary and medical geneticists.
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72
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Doyle JM, Willoughby JR, Bell DA, Bloom PH, Bragin EA, Fernandez NB, Katzner TE, Leonard K, DeWoody JA. Elevated Heterozygosity in Adults Relative to Juveniles Provides Evidence of Viability Selection on Eagles and Falcons. J Hered 2019; 110:696-706. [DOI: 10.1093/jhered/esz048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 08/01/2019] [Indexed: 02/06/2023] Open
Abstract
AbstractViability selection yields adult populations that are more genetically variable than those of juveniles, producing a positive correlation between heterozygosity and survival. Viability selection could be the result of decreased heterozygosity across many loci in inbred individuals and a subsequent decrease in survivorship resulting from the expression of the deleterious alleles. Alternatively, locus-specific differences in genetic variability between adults and juveniles may be driven by forms of balancing selection, including heterozygote advantage, frequency-dependent selection, or selection across temporal and spatial scales. We use a pooled-sequencing approach to compare genome-wide and locus-specific genetic variability between 74 golden eagle (Aquila chrysaetos), 62 imperial eagle (Aquila heliaca), and 69 prairie falcon (Falco mexicanus) juveniles and adults. Although genome-wide genetic variability is comparable between juvenile and adult golden eagles and prairie falcons, imperial eagle adults are significantly more heterozygous than juveniles. This evidence of viability selection may stem from a relatively smaller imperial eagle effective population size and potentially greater genetic load. We additionally identify ~2000 single-nucleotide polymorphisms across the 3 species with extreme differences in heterozygosity between juveniles and adults. Many of these markers are associated with genes implicated in immune function or olfaction. These loci represent potential targets for studies of how heterozygote advantage, frequency-dependent selection, and selection over spatial and temporal scales influence survivorship in avian species. Overall, our genome-wide data extend previous studies that used allozyme or microsatellite markers and indicate that viability selection may be a more common evolutionary phenomenon than often appreciated.
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Affiliation(s)
- Jacqueline M Doyle
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
| | - Janna R Willoughby
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama
- Department of Biological Sciences, Purdue University, West Lafayette, IN
| | - Douglas A Bell
- Department of Biological Sciences, Towson University, Baltimore, MD
- East Bay Regional Park District, Oakland, CA
- Department of Ornithology and Mammalogy, California Academy of Sciences, San Francisco, CA
| | - Peter H Bloom
- Department of Biological Sciences, Towson University, Baltimore, MD
- Bloom Research Inc., Los Angeles, CA
| | - Evgeny A Bragin
- Department of Biological Sciences, Towson University, Baltimore, MD
- Faculty of Natural Science, Kostanay State Pedagogical University, Kostanay, Kazakhstan
- The Peregrine Fund, Boise, ID
- Science Department, Naurzum National Nature Reserve, Kostanay Oblast, Naurzumski Raijon, Karamendy, Kazakhstan
| | - Nadia B Fernandez
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA
| | - Todd E Katzner
- Department of Biological Sciences, Towson University, Baltimore, MD
- US Geological Survey, Forest and Rangeland Ecosystem Science Center, Boise, ID
| | - Kolbe Leonard
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Computer and Information Sciences, Towson University, Baltimore, MD
| | - J Andrew DeWoody
- Department of Biological Sciences, Towson University, Baltimore, MD
- Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN
- Department of Biological Sciences, Purdue University, West Lafayette, IN
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73
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Davydov II, Salamin N, Robinson-Rechavi M. Large-Scale Comparative Analysis of Codon Models Accounting for Protein and Nucleotide Selection. Mol Biol Evol 2019; 36:1316-1332. [PMID: 30847475 PMCID: PMC6526913 DOI: 10.1093/molbev/msz048] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
There are numerous sources of variation in the rate of synonymous substitutions inside genes, such as direct selection on the nucleotide sequence, or mutation rate variation. Yet scans for positive selection rely on codon models which incorporate an assumption of effectively neutral synonymous substitution rate, constant between sites of each gene. Here we perform a large-scale comparison of approaches which incorporate codon substitution rate variation and propose our own simple yet effective modification of existing models. We find strong effects of substitution rate variation on positive selection inference. More than 70% of the genes detected by the classical branch-site model are presumably false positives caused by the incorrect assumption of uniform synonymous substitution rate. We propose a new model which is strongly favored by the data while remaining computationally tractable. With the new model we can capture signatures of nucleotide level selection acting on translation initiation and on splicing sites within the coding region. Finally, we show that rate variation is highest in the highly recombining regions, and we propose that recombination and mutation rate variation, such as high CpG mutation rate, are the two main sources of nucleotide rate variation. Although we detect fewer genes under positive selection in Drosophila than without rate variation, the genes which we detect contain a stronger signal of adaptation of dynein, which could be associated with Wolbachia infection. We provide software to perform positive selection analysis using the new model.
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Affiliation(s)
- Iakov I Davydov
- Department of Computational Biology, Biophore, University of Lausanne, Lausanne, Switzerland.,Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nicolas Salamin
- Department of Computational Biology, Biophore, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Marc Robinson-Rechavi
- Department of Ecology and Evolution, Biophore, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics, Lausanne, Switzerland
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74
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Genome-wide analysis indicates association between heterozygote advantage and healthy aging in humans. BMC Genet 2019; 20:52. [PMID: 31266448 PMCID: PMC6604157 DOI: 10.1186/s12863-019-0758-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 06/20/2019] [Indexed: 11/25/2022] Open
Abstract
Background Genetic diversity is known to confer survival advantage in many species across the tree of life. Here, we hypothesize that such pattern applies to humans as well and could be a result of higher fitness in individuals with higher genomic heterozygosity. Results We use healthy aging as a proxy for better health and fitness, and observe greater heterozygosity in healthy-aged individuals. Specifically, we find that only common genetic variants show significantly higher excess of heterozygosity in the healthy-aged cohort. Lack of difference in heterozygosity for low-frequency variants or disease-associated variants excludes the possibility of compensation for deleterious recessive alleles as a mechanism. In addition, coding SNPs with the highest excess of heterozygosity in the healthy-aged cohort are enriched in genes involved in extracellular matrix and glycoproteins, a group of genes known to be under long-term balancing selection. We also find that individual heterozygosity rate is a significant predictor of electronic health record (EHR)-based estimates of 10-year survival probability in men but not in women, accounting for several factors including age and ethnicity. Conclusions Our results demonstrate that the genomic heterozygosity is associated with human healthspan, and that the relationship between higher heterozygosity and healthy aging could be explained by heterozygote advantage. Further characterization of this relationship will have important implications in aging-associated disease risk prediction. Electronic supplementary material The online version of this article (10.1186/s12863-019-0758-4) contains supplementary material, which is available to authorized users.
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75
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Harpur BA, Guarna MM, Huxter E, Higo H, Moon KM, Hoover SE, Ibrahim A, Melathopoulos AP, Desai S, Currie RW, Pernal SF, Foster LJ, Zayed A. Integrative Genomics Reveals the Genetics and Evolution of the Honey Bee's Social Immune System. Genome Biol Evol 2019; 11:937-948. [PMID: 30768172 PMCID: PMC6447389 DOI: 10.1093/gbe/evz018] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2019] [Indexed: 12/13/2022] Open
Abstract
Social organisms combat pathogens through individual innate immune responses or through social immunity—behaviors among individuals that limit pathogen transmission within groups. Although we have a relatively detailed understanding of the genetics and evolution of the innate immune system of animals, we know little about social immunity. Addressing this knowledge gap is crucial for understanding how life-history traits influence immunity, and identifying if trade-offs exist between innate and social immunity. Hygienic behavior in the Western honey bee, Apis mellifera, provides an excellent model for investigating the genetics and evolution of social immunity in animals. This heritable, colony-level behavior is performed by nurse bees when they detect and remove infected or dead brood from the colony. We sequenced 125 haploid genomes from two artificially selected highly hygienic populations and a baseline unselected population. Genomic contrasts allowed us to identify a minimum of 73 genes tentatively associated with hygienic behavior. Many genes were within previously discovered QTLs associated with hygienic behavior and were predictive of hygienic behavior within the unselected population. These genes were often involved in neuronal development and sensory perception in solitary insects. We found that genes associated with hygienic behavior have evidence of positive selection within honey bees (Apis), supporting the hypothesis that social immunity contributes to fitness. Our results indicate that genes influencing developmental neurobiology and behavior in solitary insects may have been co-opted to give rise to a novel and adaptive social immune phenotype in honey bees.
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Affiliation(s)
- Brock A Harpur
- Department of Entomology, Purdue University.,Department of Biology, York University, Toronto, Ontario, Canada
| | - Maria Marta Guarna
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada.,Agriculture and Agri-Food Canada, Beaverlodge Research Farm, Beaverlodge, Alberta, Canada
| | | | - Heather Higo
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shelley E Hoover
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada.,Agriculture and Agri-Food Canada, Beaverlodge Research Farm, Beaverlodge, Alberta, Canada.,Alberta Agriculture and Forestry, Agriculture Centre, Lethbridge, Alberta, Canada
| | - Abdullah Ibrahim
- Agriculture and Agri-Food Canada, Beaverlodge Research Farm, Beaverlodge, Alberta, Canada
| | - Andony P Melathopoulos
- Agriculture and Agri-Food Canada, Beaverlodge Research Farm, Beaverlodge, Alberta, Canada.,Department of Horticulture, College of Agricultural Sciences, Oregon State University
| | - Suresh Desai
- Department of Entomology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Robert W Currie
- Department of Entomology, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Stephen F Pernal
- Agriculture and Agri-Food Canada, Beaverlodge Research Farm, Beaverlodge, Alberta, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amro Zayed
- Department of Biology, York University, Toronto, Ontario, Canada
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76
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Lewis PA. Leucine rich repeat kinase 2: a paradigm for pleiotropy. J Physiol 2019; 597:3511-3521. [PMID: 31124140 DOI: 10.1113/jp276163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022] Open
Abstract
The LRRK2 gene, coding for leucine rich repeat kinase 2 (LRRK2), is a key player in the genetics of Parkinson's disease. Despite extensive efforts, LRRK2 has proved remarkably evasive with regard to attempts to understand both the role it plays in disease and its normal physiological function. At least part of why LRRK2 has been so difficult to define is that it appears to be many things to many cellular functions and diseases - a pleiotropic actor at both the genetic and the molecular level. Gaining greater insight into the mechanisms and pathways allowing LRRK2 to act in this manner will have implications for our understanding of the role of genes in the aetiology of complex disease, the molecular underpinnings of signal transduction pathways in the cell, and drug discovery in the genome era.
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Affiliation(s)
- Patrick A Lewis
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AP, UK.,Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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77
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Laval G, Peyrégne S, Zidane N, Harmant C, Renaud F, Patin E, Prugnolle F, Quintana-Murci L. Recent Adaptive Acquisition by African Rainforest Hunter-Gatherers of the Late Pleistocene Sickle-Cell Mutation Suggests Past Differences in Malaria Exposure. Am J Hum Genet 2019; 104:553-561. [PMID: 30827499 PMCID: PMC6407493 DOI: 10.1016/j.ajhg.2019.02.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/04/2019] [Indexed: 12/31/2022] Open
Abstract
The hemoglobin βS sickle mutation is a textbook case in which natural selection maintains a deleterious mutation at high frequency in the human population. Homozygous individuals for this mutation develop sickle-cell disease, whereas heterozygotes benefit from higher protection against severe malaria. Because the overdominant βS allele should be purged almost immediately from the population in the absence of malaria, the study of the evolutionary history of this iconic mutation can provide important information about the history of human exposure to malaria. Here, we sought to increase our understanding of the origins and time depth of the βS mutation in populations with different lifestyles and ecologies, and we analyzed the diversity of HBB in 479 individuals from 13 populations of African farmers and rainforest hunter-gatherers. Using an approximate Bayesian computation method, we estimated the age of the βS allele while explicitly accounting for population subdivision, past demography, and balancing selection. When the effects of balancing selection are taken into account, our analyses indicate a single emergence of βS in the ancestors of present-day agriculturalist populations ∼22,000 years ago. Furthermore, we show that rainforest hunter-gatherers have more recently acquired the βS mutation from the ancestors of agriculturalists through adaptive gene flow during the last ∼6,000 years. Together, our results provide evidence for a more ancient exposure to malarial pressures among the ancestors of agriculturalists than previously appreciated, and they suggest that rainforest hunter-gatherers have been increasingly exposed to malaria during the last millennia.
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Affiliation(s)
- Guillaume Laval
- Human Evolutionary Genetics Unit, Institut Pasteur, UMR 2000 Centre National de la Recherche Scientifique, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France.
| | - Stéphane Peyrégne
- Human Evolutionary Genetics Unit, Institut Pasteur, UMR 2000 Centre National de la Recherche Scientifique, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France; Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany
| | - Nora Zidane
- Human Evolutionary Genetics Unit, Institut Pasteur, UMR 2000 Centre National de la Recherche Scientifique, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France
| | - Christine Harmant
- Human Evolutionary Genetics Unit, Institut Pasteur, UMR 2000 Centre National de la Recherche Scientifique, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France
| | - François Renaud
- Laboratory MIVEGEC (Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle), UMR 5290 Centre National de la Recherche Scientifique, Institut de Rechereche pour le Développement, Montpellier 34394, France
| | - Etienne Patin
- Human Evolutionary Genetics Unit, Institut Pasteur, UMR 2000 Centre National de la Recherche Scientifique, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France
| | - Franck Prugnolle
- Laboratory MIVEGEC (Maladies Infectieuses et Vecteurs : Ecologie, Génétique, Evolution et Contrôle), UMR 5290 Centre National de la Recherche Scientifique, Institut de Rechereche pour le Développement, Montpellier 34394, France
| | - Lluis Quintana-Murci
- Human Evolutionary Genetics Unit, Institut Pasteur, UMR 2000 Centre National de la Recherche Scientifique, Paris 75015, France; Center of Bioinformatics, Biostatistics and Integrative Biology, Institut Pasteur, Paris 75015, France.
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78
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Human Immunology through the Lens of Evolutionary Genetics. Cell 2019; 177:184-199. [DOI: 10.1016/j.cell.2019.02.033] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 01/04/2023]
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79
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Koenig D, Hagmann J, Li R, Bemm F, Slotte T, Neuffer B, Wright SI, Weigel D. Long-term balancing selection drives evolution of immunity genes in Capsella. eLife 2019; 8:e43606. [PMID: 30806624 PMCID: PMC6426441 DOI: 10.7554/elife.43606] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 02/26/2019] [Indexed: 12/14/2022] Open
Abstract
Genetic drift is expected to remove polymorphism from populations over long periods of time, with the rate of polymorphism loss being accelerated when species experience strong reductions in population size. Adaptive forces that maintain genetic variation in populations, or balancing selection, might counteract this process. To understand the extent to which natural selection can drive the retention of genetic diversity, we document genomic variability after two parallel species-wide bottlenecks in the genus Capsella. We find that ancestral variation preferentially persists at immunity related loci, and that the same collection of alleles has been maintained in different lineages that have been separated for several million years. By reconstructing the evolution of the disease-related locus MLO2b, we find that divergence between ancient haplotypes can be obscured by referenced based re-sequencing methods, and that trans-specific alleles can encode substantially diverged protein sequences. Our data point to long-term balancing selection as an important factor shaping the genetics of immune systems in plants and as the predominant driver of genomic variability after a population bottleneck.
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Affiliation(s)
- Daniel Koenig
- Department of Molecular BiologyMax Planck Institute for Developmental BiologyTübingenGermany
| | - Jörg Hagmann
- Department of Molecular BiologyMax Planck Institute for Developmental BiologyTübingenGermany
| | - Rachel Li
- Department of Molecular BiologyMax Planck Institute for Developmental BiologyTübingenGermany
| | - Felix Bemm
- Department of Molecular BiologyMax Planck Institute for Developmental BiologyTübingenGermany
| | - Tanja Slotte
- Department of Ecology,Environment, and Plant SciencesStockholm UniversityStockholmSweden
| | - Barbara Neuffer
- Department of BiologyUniversity of OsnabrückOsnabrückGermany
| | - Stephen I Wright
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoCanada
| | - Detlef Weigel
- Department of Molecular BiologyMax Planck Institute for Developmental BiologyTübingenGermany
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80
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Reher D, Key FM, Andrés AM, Kelso J. Immune Gene Diversity in Archaic and Present-day Humans. Genome Biol Evol 2019; 11:232-241. [PMID: 30566634 PMCID: PMC6347564 DOI: 10.1093/gbe/evy271] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/14/2018] [Indexed: 12/19/2022] Open
Abstract
Genome-wide analyses of two Neandertals and a Denisovan have shown that these archaic humans had lower genetic heterozygosity than present-day people. A similar reduction in genetic diversity of protein-coding genes (gene diversity) was found in exome sequences of three Neandertals. Reduced gene diversity, particularly in genes involved in immunity, may have important functional consequences. In fact, it has been suggested that reduced diversity in immune genes may have contributed to Neandertal extinction. We therefore explored gene diversity in different human groups, and at different time points on the Neandertal lineage, with a particular focus on the diversity of genes involved in innate immunity and genes of the Major Histocompatibility Complex (MHC). We find that the two Neandertals and a Denisovan have similar gene diversity, all significantly lower than any present-day human. This is true across gene categories, with no gene set showing an excess decrease in diversity compared with the genome-wide average. Innate immune-related genes show a similar reduction in diversity to other genes, both in present-day and archaic humans. There is also no observable decrease in gene diversity over time in Neandertals, suggesting that there may have been no ongoing reduction in gene diversity in later Neandertals, although this needs confirmation with a larger sample size. In both archaic and present-day humans, genes with the highest levels of diversity are enriched for MHC-related functions. In fact, in archaic humans the MHC genes show evidence of having retained more diversity than genes involved only in the innate immune system.
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Affiliation(s)
- David Reher
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Felix M Key
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Archaeogenetics, Max Planck Institute for the Science of Human History, Jena, Germany
| | - Aida M Andrés
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Genetics, Evolution and Environment, UCL Genetics Institute, University College London, London, United Kingdom
| | - Janet Kelso
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
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81
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Abstract
Trans-species polymorphism has been widely used as a key sign of long-term balancing selection across multiple species. However, such sites are often rare in the genome and could result from mutational processes or technical artifacts. Few methods are yet available to specifically detect footprints of trans-species balancing selection without using trans-species polymorphic sites. In this study, we develop summary- and model-based approaches that are each specifically tailored to uncover regions of long-term balancing selection shared by a set of species by using genomic patterns of intraspecific polymorphism and interspecific fixed differences. We demonstrate that our trans-species statistics have substantially higher power than single-species approaches to detect footprints of trans-species balancing selection, and are robust to those that do not affect all tested species. We further apply our model-based methods to human and chimpanzee whole-genome sequencing data. In addition to the previously established major histocompatibility complex and malaria resistance-associated FREM3/GYPE regions, we also find outstanding genomic regions involved in barrier integrity and innate immunity, such as the GRIK1/CLDN17 intergenic region, and the SLC35F1 and ABCA13 genes. Our findings not only echo the significance of pathogen defense but also reveal novel candidates in maintaining balanced polymorphisms across human and chimpanzee lineages. Finally, we show that these trans-species statistics can be applied to and work well for an arbitrary number of species, and integrate them into open-source software packages for ease of use by the scientific community.
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Affiliation(s)
- Xiaoheng Cheng
- Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA
- Department of Biology, Pennsylvania State University, University Park, PA
| | - Michael DeGiorgio
- Department of Biology, Pennsylvania State University, University Park, PA
- Department of Statistics, Pennsylvania State University, University Park, PA
- Institute for CyberScience, Pennsylvania State University, University Park, PA
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82
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Connallon T, Sharma S, Olito C. Evolutionary Consequences of Sex-Specific Selection in Variable Environments: Four Simple Models Reveal Diverse Evolutionary Outcomes. Am Nat 2019; 193:93-105. [DOI: 10.1086/700720] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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83
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Frequent monoallelic or skewed expression for developmental genes in CNS-derived cells and evidence for balancing selection. Proc Natl Acad Sci U S A 2018; 115:E10379-E10386. [PMID: 30322913 PMCID: PMC6217436 DOI: 10.1073/pnas.1808652115] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cellular mosaicism due to monoallelic autosomal expression (MAE), with cell selection during development, is becoming increasingly recognized as prevalent in mammals, leading to interest in understanding its extent and mechanism(s). We report here use of clonal cell lines derived from the CNS of adult female [Formula: see text] hybrid (C57BL/6 X JF1) mice to characterize MAE as neural stem cells (nscs) differentiate to astrocyte-like cells (asls). We found that different subsets of genes show MAE in the two populations of cells; in each case, there is strong enrichment for genes specific to the respective developmental state. Genes that exhibit MAE are 22% of nsc-specific genes and 26% of asl-specific genes. Moreover, the promoters of genes with MAE have reduced CpG dinucleotides but increased CpG differences between the two parental mouse strains. Extending the study of variability to wild populations of mice, we found evidence for balancing selection as a contributing force in evolution of those genes showing developmental specificity (i.e., expressed in either nsc or asl), not just for genes showing MAE. Furthermore, we found that genes showing skewed allelic expression (SKE) were similarly enriched among cell type-specific genes and also showed a heightened probability of balancing selection. Thus, developmental stage-specific genes and genes with MAE or SKE seem to make up overlapping classes subject to selection for increased diversity. The implications of these results for development and evolution are discussed in the context of a model with stochastic epigenetic modifications taking place only during a relatively brief developmental window.
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84
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Im JH, Lazzaro BP. Population genetic analysis of autophagy and phagocytosis genes in Drosophila melanogaster and D. simulans. PLoS One 2018; 13:e0205024. [PMID: 30281656 PMCID: PMC6169979 DOI: 10.1371/journal.pone.0205024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 09/18/2018] [Indexed: 12/03/2022] Open
Abstract
Autophagy and phagocytosis are cellular immune mechanisms for internalization and elimination of intracellular and extracellular pathogens. Some pathogens have evolved the ability to inhibit or manipulate these processes, raising the prospect of adaptive reciprocal co-evolution by the host. We performed population genetic analyses on phagocytosis and autophagy genes in Drosophila melanogaster and D. simulans to test for molecular evolutionary signatures of immune adaptation. We found that phagocytosis and autophagy genes as a whole exhibited an elevated level of haplotype homozygosity in both species. In addition, we detected signatures of recent selection, notably in the Atg14 and Ykt6 genes in D. melanogaster and a pattern of elevated sequence divergence in the genderblind (gb) gene on the D. simulans lineage. These results suggest that the evolution of the host cellular immune system as a whole may be shaped by a dynamic conflict between Drosophila and its pathogens even without pervasive evidence of strong adaptive evolution at the individual gene level.
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Affiliation(s)
- Joo Hyun Im
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States of America.,Graduate Field of Genetics, Genomics, and Development, Cornell University, Ithaca, NY, United States of America.,Department of Entomology, Cornell University, Ithaca, NY, United States of America
| | - Brian P Lazzaro
- Cornell Institute of Host-Microbe Interactions and Disease, Cornell University, Ithaca, NY, United States of America.,Graduate Field of Genetics, Genomics, and Development, Cornell University, Ithaca, NY, United States of America.,Department of Entomology, Cornell University, Ithaca, NY, United States of America
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85
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Bitarello BD, de Filippo C, Teixeira JC, Schmidt JM, Kleinert P, Meyer D, Andrés AM. Signatures of Long-Term Balancing Selection in Human Genomes. Genome Biol Evol 2018; 10:939-955. [PMID: 29608730 PMCID: PMC5952967 DOI: 10.1093/gbe/evy054] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2018] [Indexed: 12/15/2022] Open
Abstract
Balancing selection maintains advantageous diversity in populations through various mechanisms. Although extensively explored from a theoretical perspective, an empirical understanding of its prevalence and targets lags behind our knowledge of positive selection. Here, we describe the Non-central Deviation (NCD), a simple yet powerful statistic to detect long-term balancing selection (LTBS) that quantifies how close frequencies are to expectations under LTBS, and provides the basis for a neutrality test. NCD can be applied to a single locus or genomic data, and can be implemented considering only polymorphisms (NCD1) or also considering fixed differences with respect to an outgroup (NCD2) species. Incorporating fixed differences improves power, and NCD2 has higher power to detect LTBS in humans under different frequencies of the balanced allele(s) than other available methods. Applied to genome-wide data from African and European human populations, in both cases using chimpanzee as an outgroup, NCD2 shows that, albeit not prevalent, LTBS affects a sizable portion of the genome: ∼0.6% of analyzed genomic windows and 0.8% of analyzed positions. Significant windows (P < 0.0001) contain 1.6% of SNPs in the genome, which disproportionally fall within exons and change protein sequence, but are not enriched in putatively regulatory sites. These windows overlap ∼8% of the protein-coding genes, and these have larger number of transcripts than expected by chance even after controlling for gene length. Our catalog includes known targets of LTBS but a majority of them (90%) are novel. As expected, immune-related genes are among those with the strongest signatures, although most candidates are involved in other biological functions, suggesting that LTBS potentially influences diverse human phenotypes.
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Affiliation(s)
- Bárbara D Bitarello
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil.,Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Cesare de Filippo
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - João C Teixeira
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Unit of Human Evolutionary Genetics, Institut Pasteur, Paris, France
| | - Joshua M Schmidt
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Philip Kleinert
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Computational Molecular Biology Department, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Diogo Meyer
- Department of Genetics and Evolutionary Biology, University of São Paulo, São Paulo, Brazil
| | - Aida M Andrés
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Department of Genetics, Evolution and Environment, UCL Genetics Institute, University College London, London, United Kingdom
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86
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Voorter CEM, Matern B, Tran TH, Fink A, Vidan-Jeras B, Montanic S, Fischer G, Fae I, de Santis D, Whidborne R, Andreani M, Testi M, Groeneweg M, Tilanus MGJ. Full-length extension of HLA allele sequences by HLA allele-specific hemizygous Sanger sequencing (SSBT). Hum Immunol 2018; 79:763-772. [PMID: 30107213 DOI: 10.1016/j.humimm.2018.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 08/09/2018] [Accepted: 08/09/2018] [Indexed: 12/27/2022]
Abstract
The gold standard for typing at the allele level of the highly polymorphic Human Leucocyte Antigen (HLA) gene system is sequence based typing. Since sequencing strategies have mainly focused on identification of the peptide binding groove, full-length sequence information is lacking for >90% of the HLA alleles. One of the goals of the 17th IHIWS workshop is to establish full-length sequences for as many HLA alleles as possible. In our component "Extension of HLA sequences by full-length HLA allele-specific hemizygous Sanger sequencing" we have used full-length hemizygous Sanger Sequence Based Typing to achieve this goal. We selected samples of which full length sequences were not available in the IPD-IMGT/HLA database. In total we have generated the full-length sequences of 48 HLA-A, 45 -B and 31 -C alleles. For HLA-A extended alleles, 39/48 showed no intron differences compared to the first allele of the corresponding allele group, for HLA-B this was 26/45 and for HLA-C 20/31. Comparing the intron sequences to other alleles of the same allele group revealed that in 5/48 HLA-A, 16/45 HLA-B and 8/31 HLA-C alleles the intron sequence was identical to another allele of the same allele group. In the remaining 10 cases, the sequence either showed polymorphism at a conserved nucleotide or was the result of a gene conversion event. Elucidation of the full-length sequence gives insight in the polymorphic content of the alleles and facilitates the identification of its evolutionary origin.
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Affiliation(s)
- Christina E M Voorter
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Ben Matern
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Thuong Hien Tran
- Transplantation Immunology, Heidelberg University Hospital, Heidelberg, Germany
| | - Annette Fink
- Transplantation Immunology, Heidelberg University Hospital, Heidelberg, Germany
| | - Blanka Vidan-Jeras
- Tissue Typing Center, Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia
| | - Sendi Montanic
- Tissue Typing Center, Blood Transfusion Centre of Slovenia, Ljubljana, Slovenia
| | - Gottfried Fischer
- Department for Blood Group Serology and Blood Transfusion Medicine, Medical University Vienna, Vienna, Austria
| | - Ingrid Fae
- Department for Blood Group Serology and Blood Transfusion Medicine, Medical University Vienna, Vienna, Austria
| | - Dianne de Santis
- Department of Clinical Immunology, PathWest, Royal Perth Hospital, Perth, Australia
| | - Rebecca Whidborne
- Department of Clinical Immunology, PathWest, Royal Perth Hospital, Perth, Australia
| | - Marco Andreani
- Laboratory of Immunogenetics and Transplant Biology, IME Foundation, Policlinic of the University of Tor Vergata, Rome, Italy
| | - Manuela Testi
- Laboratory of Immunogenetics and Transplant Biology, IME Foundation, Policlinic of the University of Tor Vergata, Rome, Italy
| | - Mathijs Groeneweg
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Marcel G J Tilanus
- Transplantation Immunology, Tissue Typing Laboratory, Maastricht University Medical Center, Maastricht, The Netherlands
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87
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Sundaram L, Gao H, Padigepati SR, McRae JF, Li Y, Kosmicki JA, Fritzilas N, Hakenberg J, Dutta A, Shon J, Xu J, Batzoglou S, Li X, Farh KKH. Predicting the clinical impact of human mutation with deep neural networks. Nat Genet 2018; 50:1161-1170. [PMID: 30038395 PMCID: PMC6237276 DOI: 10.1038/s41588-018-0167-z] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 05/29/2018] [Indexed: 12/20/2022]
Abstract
Millions of human genomes and exomes have been sequenced, but their clinical applications remain limited due to the difficulty of distinguishing disease-causing mutations from benign genetic variation. Here we demonstrate that common missense variants in other primate species are largely clinically benign in human, enabling pathogenic mutations to be systematically identified by the process of elimination. Using hundreds of thousands of common variants from population sequencing of six non-human primate species, we train a deep neural network that identifies pathogenic mutations in rare disease patients with 88% accuracy and enables the discovery of 14 new candidate genes in intellectual disability at genome-wide significance. Cataloging common variation from additional primate species would improve interpretation for millions of variants of uncertain significance, further advancing the clinical utility of human genome sequencing.
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Affiliation(s)
- Laksshman Sundaram
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
- Department of Computer Science, Stanford University, Stanford, CA, USA
- National Science Foundation Center for Big Learning, University of Florida, Gainesville, FL, USA
| | - Hong Gao
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - Samskruthi Reddy Padigepati
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
- National Science Foundation Center for Big Learning, University of Florida, Gainesville, FL, USA
| | - Jeremy F McRae
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - Yanjun Li
- National Science Foundation Center for Big Learning, University of Florida, Gainesville, FL, USA
| | - Jack A Kosmicki
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
- Analytic and Translational Genetics Unit (ATGU), Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Nondas Fritzilas
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - Jörg Hakenberg
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - Anindita Dutta
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - John Shon
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - Jinbo Xu
- Toyota Technological Institute at Chicago, Chicago, IL, USA
| | - Serafim Batzoglou
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA
| | - Xiaolin Li
- National Science Foundation Center for Big Learning, University of Florida, Gainesville, FL, USA
| | - Kyle Kai-How Farh
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA, USA.
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88
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Brandt DYC, César J, Goudet J, Meyer D. The Effect of Balancing Selection on Population Differentiation: A Study with HLA Genes. G3 (BETHESDA, MD.) 2018; 8:2805-2815. [PMID: 29950428 PMCID: PMC6071603 DOI: 10.1534/g3.118.200367] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 06/21/2018] [Indexed: 01/10/2023]
Abstract
Balancing selection is defined as a class of selective regimes that maintain polymorphism above what is expected under neutrality. Theory predicts that balancing selection reduces population differentiation, as measured by FST. However, balancing selection regimes in which different sets of alleles are maintained in different populations could increase population differentiation. To tackle the connection between balancing selection and population differentiation, we investigated population differentiation at the HLA genes, which constitute the most striking example of balancing selection in humans. We found that population differentiation of single nucleotide polymorphisms (SNPs) at the HLA genes is on average lower than that of SNPs in other genomic regions. We show that these results require using a computation that accounts for the dependence of FST on allele frequencies. However, in pairs of closely related populations, where genome-wide differentiation is low, differentiation at HLA is higher than in other genomic regions. Such increased population differentiation at HLA genes for recently diverged population pairs was reproduced in simulations of overdominant selection, as long as the fitness of the homozygotes differs between the diverging populations. The results give insight into a possible "divergent overdominance" mechanism for the nature of balancing selection on HLA genes across human populations.
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Affiliation(s)
- Débora Y C Brandt
- Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Jônatas César
- Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Jérôme Goudet
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, University of Lausanne, Lausanne, Switzerland
| | - Diogo Meyer
- Departamento de Genética e Biologia Evolutiva, Universidade de São Paulo, São Paulo, SP, Brazil
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89
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Dolgova O, Lao O. Evolutionary and Medical Consequences of Archaic Introgression into Modern Human Genomes. Genes (Basel) 2018; 9:E358. [PMID: 30022013 PMCID: PMC6070777 DOI: 10.3390/genes9070358] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/07/2018] [Accepted: 07/11/2018] [Indexed: 01/13/2023] Open
Abstract
The demographic history of anatomically modern humans (AMH) involves multiple migration events, population extinctions and genetic adaptations. As genome-wide data from complete genome sequencing becomes increasingly abundant and available even from extinct hominins, new insights of the evolutionary history of our species are discovered. It is currently known that AMH interbred with archaic hominins once they left the African continent. Current non-African human genomes carry fragments of archaic origin. This review focuses on the fitness consequences of archaic interbreeding in current human populations. We discuss new insights and challenges that researchers face when interpreting the potential impact of introgression on fitness and testing hypotheses about the role of selection within the context of health and disease.
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Affiliation(s)
- Olga Dolgova
- Population Genomics Group, Centre Nacional d'Anàlisi Genòmica, Centre de Regulació Genòmica (CRG-CNAG), Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Catalonia, Spain.
| | - Oscar Lao
- Population Genomics Group, Centre Nacional d'Anàlisi Genòmica, Centre de Regulació Genòmica (CRG-CNAG), Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Catalonia, Spain.
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90
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Tennessen JA. Gene buddies: linked balanced polymorphisms reinforce each other even in the absence of epistasis. PeerJ 2018; 6:e5110. [PMID: 29967750 PMCID: PMC6026533 DOI: 10.7717/peerj.5110] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/05/2018] [Indexed: 01/16/2023] Open
Abstract
The fates of genetic polymorphisms maintained by balancing selection depend on evolutionary dynamics at linked sites. While coevolution across linked, epigenetically-interacting loci has been extensively explored, such supergenes may be relatively rare. However, genes harboring adaptive variation can occur in close physical proximity while generating independent effects on fitness. Here, I present a model in which two linked loci without epistasis are both under balancing selection for unrelated reasons. Using forward-time simulations, I show that recombination rate strongly influences the retention of adaptive polymorphism, especially for intermediate selection coefficients. A locus is more likely to retain adaptive variation if it is closely linked to another locus under balancing selection, even if the two loci have no interaction. Thus, two linked polymorphisms can both be retained indefinitely even when they would both be lost to drift if unlinked. While these results may be intuitive, they have important implications for genetic architecture: clusters of mutually reinforcing genes may underlie phenotypic variation in natural populations, and such genes cannot be assumed to be functionally associated. Future studies that measure selection coefficients and recombination rates among closely linked genes will be fruitful for characterizing the extent of this phenomenon.
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Affiliation(s)
- Jacob A. Tennessen
- Department of Integrative Biology, Oregon State University, Corvallis, OR, USA
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91
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Tiemann-Boege I, Schwarz T, Striedner Y, Heissl A. The consequences of sequence erosion in the evolution of recombination hotspots. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0462. [PMID: 29109225 PMCID: PMC5698624 DOI: 10.1098/rstb.2016.0462] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2017] [Indexed: 12/18/2022] Open
Abstract
Meiosis is initiated by a double-strand break (DSB) introduced in the DNA by a highly controlled process that is repaired by recombination. In many organisms, recombination occurs at specific and narrow regions of the genome, known as recombination hotspots, which overlap with regions enriched for DSBs. In recent years, it has been demonstrated that conversions and mutations resulting from the repair of DSBs lead to a rapid sequence evolution at recombination hotspots eroding target sites for DSBs. We still do not fully understand the effect of this erosion in the recombination activity, but evidence has shown that the binding of trans-acting factors like PRDM9 is affected. PRDM9 is a meiosis-specific, multi-domain protein that recognizes DNA target motifs by its zinc finger domain and directs DSBs to these target sites. Here we discuss the changes in affinity of PRDM9 to eroded recognition sequences, and explain how these changes in affinity of PRDM9 can affect recombination, leading sometimes to sterility in the context of hybrid crosses. We also present experimental data showing that DNA methylation reduces PRDM9 binding in vitro. Finally, we discuss PRDM9-independent hotspots, posing the question how these hotspots evolve and change with sequence erosion. This article is part of the themed issue ‘Evolutionary causes and consequences of recombination rate variation in sexual organisms’.
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Affiliation(s)
- Irene Tiemann-Boege
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Theresa Schwarz
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Yasmin Striedner
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
| | - Angelika Heissl
- Institute of Biophysics, Johannes Kepler University, Linz, Gruberstraße 40, 4020 Linz, Austria
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92
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Gokcumen O. The Year In Genetic Anthropology: New Lands, New Technologies, New Questions. AMERICAN ANTHROPOLOGIST 2018. [DOI: 10.1111/aman.13032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Omer Gokcumen
- Department of Biological Sciences University of Buffalo NY 14260 USA
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93
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Zajitschek F, Connallon T. Antagonistic pleiotropy in species with separate sexes, and the maintenance of genetic variation in life-history traits and fitness. Evolution 2018; 72:1306-1316. [PMID: 29667189 DOI: 10.1111/evo.13493] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/21/2018] [Accepted: 03/23/2018] [Indexed: 01/01/2023]
Abstract
Antagonistic pleiotropy (AP)-where alleles of a gene increase some components of fitness at a cost to others-can generate balancing selection, and contribute to the maintenance of genetic variation in fitness traits, such as survival, fecundity, fertility, and mate competition. Previous theory suggests that AP is unlikely to maintain variation unless antagonistic selection is strong, or AP alleles exhibit pronounced differences in genetic dominance between the affected traits. We show that conditions for balancing selection under AP expand under the likely scenario that the strength of selection on each fitness component differs between the sexes. Our model also predicts that the vast majority of balanced polymorphisms have sexually antagonistic effects on total fitness, despite the absence of sexual antagonism for individual fitness components. We conclude that AP polymorphisms are less difficult to maintain than predicted by prior theory, even under our conservative assumption that selection on components of fitness is universally sexually concordant. We discuss implications for the maintenance of genetic variation, and for inferences of sexual antagonism that are based on sex-specific phenotypic selection estimates-many of which are based on single fitness components.
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Affiliation(s)
- Felix Zajitschek
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Tim Connallon
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
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94
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Saitou M, Satta Y, Gokcumen O, Ishida T. Complex evolution of the GSTM gene family involves sharing of GSTM1 deletion polymorphism in humans and chimpanzees. BMC Genomics 2018; 19:293. [PMID: 29695243 PMCID: PMC5918908 DOI: 10.1186/s12864-018-4676-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2018] [Accepted: 04/15/2018] [Indexed: 02/06/2023] Open
Abstract
Background The common deletion of the glutathione S-transferase Mu 1 (GSTM1) gene in humans has been shown to be involved in xenobiotic metabolism and associated with bladder cancer. However, the evolution of this deletion has not been investigated. Results In this study, we conducted comparative analyses of primate genomes. We demonstrated that the GSTM gene family has evolved through multiple structural variations, involving gene duplications, losses, large inversions and gene conversions. We further showed experimentally that the GSTM1 was polymorphically deleted in both humans and also in chimpanzees, through independent deletion events. To generalize our results, we searched for genic deletions that are polymorphic in both humans and chimpanzees. Consequently, we found only two such deletions among the thousands that we have searched, one of them being the GSTM1 deletion and the other surprisingly being another metabolizing gene, the UGT2B17. Conclusions Overall, our results support the emerging notion that metabolizing gene families, such as the GSTM, NAT, UGT and CYP, have been evolving rapidly through gene duplication and deletion events in primates, leading to complex structural variation within and among species with unknown evolutionary consequences. Electronic supplementary material The online version of this article (10.1186/s12864-018-4676-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- M Saitou
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.,Department of Biological Sciences, State University of New York at Buffalo, Buffalo, USA
| | - Y Satta
- The Graduate University for Advanced Studies (SOKENDAI), Hayama, Japan
| | - O Gokcumen
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, USA.
| | - T Ishida
- Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.
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95
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Johnson KE, Voight BF. Patterns of shared signatures of recent positive selection across human populations. Nat Ecol Evol 2018; 2:713-720. [PMID: 29459708 PMCID: PMC5866773 DOI: 10.1038/s41559-018-0478-6] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 01/11/2018] [Indexed: 12/28/2022]
Abstract
Signatures of recent positive selection often overlap across human populations, but the question of how often these overlaps represent a single ancestral event remains unresolved. If a single selective event spread across many populations, the same sweeping haplotype should appear in each population and the selective pressure could be common across populations and environments. Identifying such shared selective events could identify genomic loci and human traits important in recent history across the globe. In addition, genomic annotations that recently became available could help attach these signatures to a potential gene and molecular phenotype selected across populations. Here, we present a catalogue of selective sweeps in humans, and identify those that overlap and share a sweeping haplotype. We connect these sweep overlaps with potential biological mechanisms at several loci, including potential new sites of adaptive introgression, the glycophorin locus associated with malarial resistance and the alcohol dehydrogenase cluster associated with alcohol dependency.
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Affiliation(s)
- Kelsey Elizabeth Johnson
- Genetics and Gene Regulation Program, Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Benjamin F Voight
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
- Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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96
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Siewert KM, Voight BF. Detecting Long-Term Balancing Selection Using Allele Frequency Correlation. Mol Biol Evol 2018; 34:2996-3005. [PMID: 28981714 PMCID: PMC5850717 DOI: 10.1093/molbev/msx209] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Balancing selection occurs when multiple alleles are maintained in a population, which can result in their preservation over long evolutionary time periods. A characteristic signature of this long-term balancing selection is an excess number of intermediate frequency polymorphisms near the balanced variant. However, the expected distribution of allele frequencies at these loci has not been extensively detailed, and therefore existing summary statistic methods do not explicitly take it into account. Using simulations, we show that new mutations which arise in close proximity to a site targeted by balancing selection accumulate at frequencies nearly identical to that of the balanced allele. In order to scan the genome for balancing selection, we propose a new summary statistic, β, which detects these clusters of alleles at similar frequencies. Simulation studies show that compared with existing summary statistics, our measure has improved power to detect balancing selection, and is reasonably powered in non-equilibrium demographic models and under a range of recombination and mutation rates. We compute β on 1000 Genomes Project data to identify loci potentially subjected to long-term balancing selection in humans. We report two balanced haplotypes-localized to the genes WFS1 and CADM2-that are strongly linked to association signals for complex traits. Our approach is computationally efficient and applicable to species that lack appropriate outgroup sequences, allowing for well-powered analysis of selection in the wide variety of species for which population data are rapidly being generated.
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Affiliation(s)
- Katherine M Siewert
- Genomics and Computational Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Benjamin F Voight
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.,Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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97
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Ancient balancing selection on heterocyst function in a cosmopolitan cyanobacterium. Nat Ecol Evol 2018; 2:510-519. [DOI: 10.1038/s41559-017-0435-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 11/29/2017] [Indexed: 11/08/2022]
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98
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Hart MW, Stover DA, Guerra V, Mozaffari SV, Ober C, Mugal CF, Kaj I. Positive selection on human gamete-recognition genes. PeerJ 2018; 6:e4259. [PMID: 29340252 PMCID: PMC5767332 DOI: 10.7717/peerj.4259] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 12/21/2017] [Indexed: 01/29/2023] Open
Abstract
Coevolution of genes that encode interacting proteins expressed on the surfaces of sperm and eggs can lead to variation in reproductive compatibility between mates and reproductive isolation between members of different species. Previous studies in mice and other mammals have focused in particular on evidence for positive or diversifying selection that shapes the evolution of genes that encode sperm-binding proteins expressed in the egg coat or zona pellucida (ZP). By fitting phylogenetic models of codon evolution to data from the 1000 Genomes Project, we identified candidate sites evolving under diversifying selection in the human genes ZP3 and ZP2. We also identified one candidate site under positive selection in C4BPA, which encodes a repetitive protein similar to the mouse protein ZP3R that is expressed in the sperm head and binds to the ZP at fertilization. Results from several additional analyses that applied population genetic models to the same data were consistent with the hypothesis of selection on those candidate sites leading to coevolution of sperm- and egg-expressed genes. By contrast, we found no candidate sites under selection in a fourth gene (ZP1) that encodes an egg coat structural protein not directly involved in sperm binding. Finally, we found that two of the candidate sites (in C4BPA and ZP2) were correlated with variation in family size and birth rate among Hutterite couples, and those two candidate sites were also in linkage disequilibrium in the same Hutterite study population. All of these lines of evidence are consistent with predictions from a previously proposed hypothesis of balancing selection on epistatic interactions between C4BPA and ZP3 at fertilization that lead to the evolution of co-adapted allele pairs. Such patterns also suggest specific molecular traits that may be associated with both natural reproductive variation and clinical infertility.
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Affiliation(s)
- Michael W Hart
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Daryn A Stover
- School of Mathematical and Natural Sciences, Arizona State University Colleges at Lake Havasu City, Lake Havasu City, AZ, USA
| | - Vanessa Guerra
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Sahar V Mozaffari
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Carole Ober
- Department of Human Genetics, University of Chicago, Chicago, IL, USA
| | - Carina F Mugal
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Ingemar Kaj
- Department of Mathematics, Uppsala University, Uppsala, Sweden
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99
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Ravenhall M, Campino S, Sepúlveda N, Manjurano A, Nadjm B, Mtove G, Wangai H, Maxwell C, Olomi R, Reyburn H, Drakeley CJ, Riley EM, Clark TG. Novel genetic polymorphisms associated with severe malaria and under selective pressure in North-eastern Tanzania. PLoS Genet 2018; 14:e1007172. [PMID: 29381699 PMCID: PMC5806895 DOI: 10.1371/journal.pgen.1007172] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 02/09/2018] [Accepted: 12/29/2017] [Indexed: 01/07/2023] Open
Abstract
Significant selection pressure has been exerted on the genomes of human populations exposed to Plasmodium falciparum infection, resulting in the acquisition of mechanisms of resistance against severe malarial disease. Many host genetic factors, including sickle cell trait, have been associated with reduced risk of developing severe malaria, but do not account for all of the observed phenotypic variation. Identification of novel inherited risk factors relies upon high-resolution genome-wide association studies (GWAS). We present findings of a GWAS of severe malaria performed in a Tanzanian population (n = 914, 15.2 million SNPs). Beyond the expected association with the sickle cell HbS variant, we identify protective associations within two interleukin receptors (IL-23R and IL-12RBR2) and the kelch-like protein KLHL3 (all P<10-6), as well as near significant effects for Major Histocompatibility Complex (MHC) haplotypes. Complementary analyses, based on detecting extended haplotype homozygosity, identified SYNJ2BP, GCLC and MHC as potential loci under recent positive selection. Through whole genome sequencing of an independent Tanzanian cohort (parent-child trios n = 247), we confirm the allele frequencies of common polymorphisms underlying associations and selection, as well as the presence of multiple structural variants that could be in linkage with these SNPs. Imputation of structural variants in a region encompassing the glycophorin genes on chromosome 4, led to the characterisation of more than 50 rare variants, and individually no strong evidence of associations with severe malaria in our primary dataset (P>0.3). Our approach demonstrates the potential of a joint genotyping-sequencing strategy to identify as-yet unknown susceptibility loci in an African population with well-characterised malaria phenotypes. The regions encompassing these loci are potential targets for the design of much needed interventions for preventing or treating malarial disease.
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Affiliation(s)
- Matt Ravenhall
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Susana Campino
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Nuno Sepúlveda
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Centre for Statistics and Applications, University of Lisbon, Lisbon, Portugal
| | - Alphaxard Manjurano
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
- National Institute for Medical Research, Mwanza, Tanzania
| | - Behzad Nadjm
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - George Mtove
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Hannah Wangai
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Caroline Maxwell
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Raimos Olomi
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Hugh Reyburn
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Christopher J. Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Eleanor M. Riley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Joint Malaria Programme, Kilimanjaro Christian Medical College, Moshi, Tanzania
| | - Taane G. Clark
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Department of Infectious Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
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100
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Meyer D, C Aguiar VR, Bitarello BD, C Brandt DY, Nunes K. A genomic perspective on HLA evolution. Immunogenetics 2018; 70:5-27. [PMID: 28687858 PMCID: PMC5748415 DOI: 10.1007/s00251-017-1017-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 06/16/2017] [Indexed: 12/20/2022]
Abstract
Several decades of research have convincingly shown that classical human leukocyte antigen (HLA) loci bear signatures of natural selection. Despite this conclusion, many questions remain regarding the type of selective regime acting on these loci, the time frame at which selection acts, and the functional connections between genetic variability and natural selection. In this review, we argue that genomic datasets, in particular those generated by next-generation sequencing (NGS) at the population scale, are transforming our understanding of HLA evolution. We show that genomewide data can be used to perform robust and powerful tests for selection, capable of identifying both positive and balancing selection at HLA genes. Importantly, these tests have shown that natural selection can be identified at both recent and ancient timescales. We discuss how findings from genomewide association studies impact the evolutionary study of HLA genes, and how genomic data can be used to survey adaptive change involving interaction at multiple loci. We discuss the methodological developments which are necessary to correctly interpret genomic analyses involving the HLA region. These developments include adapting the NGS analysis framework so as to deal with the highly polymorphic HLA data, as well as developing tools and theory to search for signatures of selection, quantify differentiation, and measure admixture within the HLA region. Finally, we show that high throughput analysis of molecular phenotypes for HLA genes-namely transcription levels-is now a feasible approach and can add another dimension to the study of genetic variation.
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Affiliation(s)
- Diogo Meyer
- Department of Genetics and Evolutionary Biology, University of São Paulo, 05508-090, São Paulo, SP, Brazil.
| | - Vitor R C Aguiar
- Department of Genetics and Evolutionary Biology, University of São Paulo, 05508-090, São Paulo, SP, Brazil
| | - Bárbara D Bitarello
- Department of Genetics and Evolutionary Biology, University of São Paulo, 05508-090, São Paulo, SP, Brazil
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Débora Y C Brandt
- Department of Genetics and Evolutionary Biology, University of São Paulo, 05508-090, São Paulo, SP, Brazil
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Kelly Nunes
- Department of Genetics and Evolutionary Biology, University of São Paulo, 05508-090, São Paulo, SP, Brazil
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