101
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Ottolini B, Hornsby MJ, Abujaber R, MacArthur JAL, Badge RM, Schwarzacher T, Albertson DG, Bevins CL, Solnick JV, Hollox EJ. Evidence of convergent evolution in humans and macaques supports an adaptive role for copy number variation of the β-defensin-2 gene. Genome Biol Evol 2014; 6:3025-38. [PMID: 25349268 PMCID: PMC4255768 DOI: 10.1093/gbe/evu236] [Citation(s) in RCA: 18] [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] [Indexed: 12/12/2022] Open
Abstract
β-defensins are a family of important peptides of innate immunity, involved in host defense, immunomodulation, reproduction, and pigmentation. Genes encoding β-defensins show evidence of birth-and-death evolution, adaptation by amino acid sequence changes, and extensive copy number variation (CNV) within humans and other species. The role of CNV in the adaptation of β-defensins to new functions remains unclear, as does the adaptive role of CNV in general. Here, we fine-map CNV of a cluster of β-defensins in humans and rhesus macaques. Remarkably, we found that the structure of the CNV is different between primates, with distinct mutational origins and CNV boundaries defined by retroviral long terminal repeat elements. Although the human β-defensin CNV region is 322 kb and encompasses several genes, including β-defensins, a long noncoding RNA gene, and testes-specific zinc-finger transcription factors, the orthologous region in the rhesus macaque shows CNV of a 20-kb region, containing only a single gene, the ortholog of the human β-defensin-2 gene. Despite its independent origins, the range of gene copy numbers in the rhesus macaque is similar to humans. In addition, the rhesus macaque gene has been subject to divergent positive selection at the amino acid level following its initial duplication event between 3 and 9.5 Ma, suggesting adaptation of this gene as the macaque successfully colonized novel environments outside Africa. Therefore, the molecular phenotype of β-defensin-2 CNV has undergone convergent evolution, and this gene shows evidence of adaptation at the amino acid level in rhesus macaques.
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Affiliation(s)
| | - Michael J Hornsby
- Department of Microbiology and Immunology, University of California Davis School of Medicine
| | - Razan Abujaber
- Department of Genetics, University of Leicester, United Kingdom
| | - Jacqueline A L MacArthur
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco Present address: European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Richard M Badge
- Department of Genetics, University of Leicester, United Kingdom
| | | | - Donna G Albertson
- Helen Diller Family Comprehensive Cancer Center, University of California San Francisco Present address: Bluestone Center for Clinical Research, New York University College of Dentistry, New York, New York
| | - Charles L Bevins
- Department of Microbiology and Immunology, University of California Davis School of Medicine
| | - Jay V Solnick
- Department of Microbiology and Immunology, University of California Davis School of Medicine Department of Medicine, Center for Comparative Medicine, and the California National Primate Research Center, University of California
| | - Edward J Hollox
- Department of Genetics, University of Leicester, United Kingdom
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102
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Palindromic GOLGA8 core duplicons promote chromosome 15q13.3 microdeletion and evolutionary instability. Nat Genet 2014; 46:1293-302. [PMID: 25326701 PMCID: PMC4244265 DOI: 10.1038/ng.3120] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Accepted: 09/25/2014] [Indexed: 12/14/2022]
Abstract
Recurrent deletions of chromosome 15q13.3 associate with intellectual disability, schizophrenia, autism and epilepsy. To gain insight into its instability, we sequenced the region in patients, normal individuals and nonhuman primates. We discovered five structural configurations of the human chromosome 15q13.3 region ranging in size from 2 to 3 Mbp. These configurations arose recently (~0.5–0.9 million years ago) as a result of human-specific expansions of segmental duplications and two independent inversion events. All inversion breakpoints map near GOLGA8 core duplicons—a ~14 kbp primate-specific chromosome 15 repeat that became organized into larger palindromic structures. GOLGA8-flanked palindromes also demarcate the breakpoints of recurrent 15q13.3 microdeletions, the expansion of chromosome 15 segmental duplications in the human lineage, and independent structural changes in apes. The significant clustering (p=0.002) of breakpoints provides mechanistic evidence for the role of this core duplicon and its palindromic architecture in promoting evolutionary and disease-related instability of chromosome 15.
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103
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Perdomo-Sabogal A, Kanton S, Walter MBC, Nowick K. The role of gene regulatory factors in the evolutionary history of humans. Curr Opin Genet Dev 2014; 29:60-7. [PMID: 25215414 DOI: 10.1016/j.gde.2014.08.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/05/2014] [Accepted: 08/22/2014] [Indexed: 01/01/2023]
Abstract
Deciphering the molecular basis of how modern human phenotypes have evolved is one of the most fascinating challenges in biology. Here, we will focus on the roles of gene regulatory factors (GRFs), in particular transcription factors (TFs) and long non-coding RNAs (lncRNAs) during human evolution. We will present examples of TFs and lncRNAs that have changed or show signs of positive selection in humans compared to chimpanzees, in modern humans compared to archaic humans, or within modern human populations. On the basis of current knowledge about the functions of these GRF genes, we speculate that they have been involved in speciation as well as in shaping phenotypes such as brain functions, skeletal morphology, and metabolic processes.
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Affiliation(s)
- Alvaro Perdomo-Sabogal
- TFome Research Group, Bioinformatics Group, Interdisciplinary Center of Bioinformatics, Department of Computer Science, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany; Paul-Flechsig-Institute for Brain Research, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany
| | - Sabina Kanton
- TFome Research Group, Bioinformatics Group, Interdisciplinary Center of Bioinformatics, Department of Computer Science, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany; Paul-Flechsig-Institute for Brain Research, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany
| | - Maria Beatriz C Walter
- TFome Research Group, Bioinformatics Group, Interdisciplinary Center of Bioinformatics, Department of Computer Science, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany; Paul-Flechsig-Institute for Brain Research, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany
| | - Katja Nowick
- TFome Research Group, Bioinformatics Group, Interdisciplinary Center of Bioinformatics, Department of Computer Science, University of Leipzig, Härtelstrasse 16-18, D-04107 Leipzig, Germany; Paul-Flechsig-Institute for Brain Research, University of Leipzig, Jahnallee 59, D-04109 Leipzig, Germany.
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104
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Fontenot M, Konopka G. Molecular networks and the evolution of human cognitive specializations. Curr Opin Genet Dev 2014; 29:52-9. [PMID: 25212263 DOI: 10.1016/j.gde.2014.08.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/12/2014] [Accepted: 08/23/2014] [Indexed: 12/25/2022]
Abstract
Inroads into elucidating the origins of human cognitive specializations have taken many forms, including genetic, genomic, anatomical, and behavioral assays that typically compare humans to non-human primates. While the integration of all of these approaches is essential for ultimately understanding human cognition, here, we review the usefulness of coexpression network analysis for specifically addressing this question. An increasing number of studies have incorporated coexpression networks into brain expression studies comparing species, disease versus control tissue, brain regions, or developmental time periods. A clearer picture has emerged of the key genes driving brain evolution, as well as the developmental and regional contributions of gene expression patterns important for normal brain development and those misregulated in cognitive diseases.
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Affiliation(s)
- Miles Fontenot
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, USA
| | - Genevieve Konopka
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, USA.
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105
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Skinner MK, Gurerrero-Bosagna C, Haque MM, Nilsson EE, Koop JAH, Knutie SA, Clayton DH. Epigenetics and the evolution of Darwin's Finches. Genome Biol Evol 2014; 6:1972-89. [PMID: 25062919 PMCID: PMC4159007 DOI: 10.1093/gbe/evu158] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The prevailing theory for the molecular basis of evolution involves genetic mutations that ultimately generate the heritable phenotypic variation on which natural selection acts. However, epigenetic transgenerational inheritance of phenotypic variation may also play an important role in evolutionary change. A growing number of studies have demonstrated the presence of epigenetic inheritance in a variety of different organisms that can persist for hundreds of generations. The possibility that epigenetic changes can accumulate over longer periods of evolutionary time has seldom been tested empirically. This study was designed to compare epigenetic changes among several closely related species of Darwin's finches, a well-known example of adaptive radiation. Erythrocyte DNA was obtained from five species of sympatric Darwin's finches that vary in phylogenetic relatedness. Genome-wide alterations in genetic mutations using copy number variation (CNV) were compared with epigenetic alterations associated with differential DNA methylation regions (epimutations). Epimutations were more common than genetic CNV mutations among the five species; furthermore, the number of epimutations increased monotonically with phylogenetic distance. Interestingly, the number of genetic CNV mutations did not consistently increase with phylogenetic distance. The number, chromosomal locations, regional clustering, and lack of overlap of epimutations and genetic mutations suggest that epigenetic changes are distinct and that they correlate with the evolutionary history of Darwin's finches. The potential functional significance of the epimutations was explored by comparing their locations on the genome to the location of evolutionarily important genes and cellular pathways in birds. Specific epimutations were associated with genes related to the bone morphogenic protein, toll receptor, and melanogenesis signaling pathways. Species-specific epimutations were significantly overrepresented in these pathways. As environmental factors are known to result in heritable changes in the epigenome, it is possible that epigenetic changes contribute to the molecular basis of the evolution of Darwin's finches.
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Affiliation(s)
- Michael K Skinner
- Center for Reproductive Biology, School of Biological Sciences, Washington State University
| | - Carlos Gurerrero-Bosagna
- Center for Reproductive Biology, School of Biological Sciences, Washington State UniversityPresent address: Department of Physics, Biology and Chemistry (IFM), Linköping University, Sweden
| | - M Muksitul Haque
- Center for Reproductive Biology, School of Biological Sciences, Washington State University
| | - Eric E Nilsson
- Center for Reproductive Biology, School of Biological Sciences, Washington State University
| | - Jennifer A H Koop
- Department of Biology, University of UtahPresent address: Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ
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106
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Keane TM, Wong K, Adams DJ, Flint J, Reymond A, Yalcin B. Identification of structural variation in mouse genomes. Front Genet 2014; 5:192. [PMID: 25071822 PMCID: PMC4079067 DOI: 10.3389/fgene.2014.00192] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 06/12/2014] [Indexed: 01/25/2023] Open
Abstract
Structural variation is variation in structure of DNA regions affecting DNA sequence length and/or orientation. It generally includes deletions, insertions, copy-number gains, inversions, and transposable elements. Traditionally, the identification of structural variation in genomes has been challenging. However, with the recent advances in high-throughput DNA sequencing and paired-end mapping (PEM) methods, the ability to identify structural variation and their respective association to human diseases has improved considerably. In this review, we describe our current knowledge of structural variation in the mouse, one of the prime model systems for studying human diseases and mammalian biology. We further present the evolutionary implications of structural variation on transposable elements. We conclude with future directions on the study of structural variation in mouse genomes that will increase our understanding of molecular architecture and functional consequences of structural variation.
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Affiliation(s)
| | - Kim Wong
- Wellcome Trust Sanger Institute Hinxton, Cambridge, UK
| | - David J Adams
- Wellcome Trust Sanger Institute Hinxton, Cambridge, UK
| | | | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne Lausanne, Switzerland
| | - Binnaz Yalcin
- Center for Integrative Genomics, University of Lausanne Lausanne, Switzerland ; Institute of Genetics and Molecular and Cellular Biology Illkirch, France
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107
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Giannuzzi G, Migliavacca E, Reymond A. Novel H3K4me3 marks are enriched at human- and chimpanzee-specific cytogenetic structures. Genome Res 2014; 24:1455-68. [PMID: 24916972 PMCID: PMC4158755 DOI: 10.1101/gr.167742.113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human and chimpanzee genomes are 98.8% identical within comparable sequences. However, they differ structurally in nine pericentric inversions, one fusion that originated human chromosome 2, and content and localization of heterochromatin and lineage-specific segmental duplications. The possible functional consequences of these cytogenetic and structural differences are not fully understood and their possible involvement in speciation remains unclear. We show that subtelomeric regions—regions that have a species-specific organization, are more divergent in sequence, and are enriched in genes and recombination hotspots—are significantly enriched for species-specific histone modifications that decorate transcription start sites in different tissues in both human and chimpanzee. The human lineage-specific chromosome 2 fusion point and ancestral centromere locus as well as chromosome 1 and 18 pericentric inversion breakpoints showed enrichment of human-specific H3K4me3 peaks in the prefrontal cortex. Our results reveal an association between plastic regions and potential novel regulatory elements.
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Affiliation(s)
- Giuliana Giannuzzi
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland;
| | - Eugenia Migliavacca
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland;
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108
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Abstract
Research into when and where modern humans originated and how they differ from, and interacted with, other now-extinct forms of human has so far been the realm of archaeologists and paleoanthropologists. However, over the past decade, molecular geneticists have begun to study genomes of extinct humans. Here, I discuss where we stand today with respect to understanding how modern humans came to differ from Neandertals and other human forms that existed until about 30,000 years ago.
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Affiliation(s)
- Svante Pääbo
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Anthropology, D-04103 Leipzig, Germany.
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109
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Lucas-Lledó JI, Vicente-Salvador D, Aguado C, Cáceres M. Population genetic analysis of bi-allelic structural variants from low-coverage sequence data with an expectation-maximization algorithm. BMC Bioinformatics 2014; 15:163. [PMID: 24884587 PMCID: PMC4055234 DOI: 10.1186/1471-2105-15-163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 05/14/2014] [Indexed: 11/21/2022] Open
Abstract
Background Population genetics and association studies usually rely on a set of known variable sites that are then genotyped in subsequent samples, because it is easier to genotype than to discover the variation. This is also true for structural variation detected from sequence data. However, the genotypes at known variable sites can only be inferred with uncertainty from low coverage data. Thus, statistical approaches that infer genotype likelihoods, test hypotheses, and estimate population parameters without requiring accurate genotypes are becoming popular. Unfortunately, the current implementations of these methods are intended to analyse only single nucleotide and short indel variation, and they usually assume that the two alleles in a heterozygous individual are sampled with equal probability. This is generally false for structural variants detected with paired ends or split reads. Therefore, the population genetics of structural variants cannot be studied, unless a painstaking and potentially biased genotyping is performed first. Results We present svgem, an expectation-maximization implementation to estimate allele and genotype frequencies, calculate genotype posterior probabilities, and test for Hardy-Weinberg equilibrium and for population differences, from the numbers of times the alleles are observed in each individual. Although applicable to single nucleotide variation, it aims at bi-allelic structural variation of any type, observed by either split reads or paired ends, with arbitrarily high allele sampling bias. We test svgem with simulated and real data from the 1000 Genomes Project. Conclusions svgem makes it possible to use low-coverage sequencing data to study the population distribution of structural variants without having to know their genotypes. Furthermore, this advance allows the combined analysis of structural and nucleotide variation within the same genotype-free statistical framework, thus preventing biases introduced by genotype imputation.
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Affiliation(s)
- José Ignacio Lucas-Lledó
- Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain.
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110
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Watson CT, Marques-Bonet T, Sharp AJ, Mefford HC. The genetics of microdeletion and microduplication syndromes: an update. Annu Rev Genomics Hum Genet 2014; 15:215-244. [PMID: 24773319 DOI: 10.1146/annurev-genom-091212-153408] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chromosomal abnormalities, including microdeletions and microduplications, have long been associated with abnormal developmental outcomes. Early discoveries relied on a common clinical presentation and the ability to detect chromosomal abnormalities by standard karyotype analysis or specific assays such as fluorescence in situ hybridization. Over the past decade, the development of novel genomic technologies has allowed more comprehensive, unbiased discovery of microdeletions and microduplications throughout the human genome. The ability to quickly interrogate large cohorts using chromosome microarrays and, more recently, next-generation sequencing has led to the rapid discovery of novel microdeletions and microduplications associated with disease, including very rare but clinically significant rearrangements. In addition, the observation that some microdeletions are associated with risk for several neurodevelopmental disorders contributes to our understanding of shared genetic susceptibility for such disorders. Here, we review current knowledge of microdeletion/duplication syndromes, with a particular focus on recurrent rearrangement syndromes.
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Affiliation(s)
- Corey T Watson
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Tomas Marques-Bonet
- Institut de Biologia Evolutiva, Universitat Pompeu Fabra/CSIC, 08003 Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain.,Centro Nacional de Análisis Genómico, 08023 Barcelona, Spain
| | - Andrew J Sharp
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Heather C Mefford
- Department of Pediatrics, University of Washington, Seattle, Washington 98195
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111
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Bergström A, Simpson JT, Salinas F, Barré B, Parts L, Zia A, Nguyen Ba AN, Moses AM, Louis EJ, Mustonen V, Warringer J, Durbin R, Liti G. A high-definition view of functional genetic variation from natural yeast genomes. Mol Biol Evol 2014; 31:872-88. [PMID: 24425782 PMCID: PMC3969562 DOI: 10.1093/molbev/msu037] [Citation(s) in RCA: 207] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The question of how genetic variation in a population influences phenotypic variation and evolution is of major importance in modern biology. Yet much is still unknown about the relative functional importance of different forms of genome variation and how they are shaped by evolutionary processes. Here we address these questions by population level sequencing of 42 strains from the budding yeast Saccharomyces cerevisiae and its closest relative S. paradoxus. We find that genome content variation, in the form of presence or absence as well as copy number of genetic material, is higher within S. cerevisiae than within S. paradoxus, despite genetic distances as measured in single-nucleotide polymorphisms being vastly smaller within the former species. This genome content variation, as well as loss-of-function variation in the form of premature stop codons and frameshifting indels, is heavily enriched in the subtelomeres, strongly reinforcing the relevance of these regions to functional evolution. Genes affected by these likely functional forms of variation are enriched for functions mediating interaction with the external environment (sugar transport and metabolism, flocculation, metal transport, and metabolism). Our results and analyses provide a comprehensive view of genomic diversity in budding yeast and expose surprising and pronounced differences between the variation within S. cerevisiae and that within S. paradoxus. We also believe that the sequence data and de novo assemblies will constitute a useful resource for further evolutionary and population genomics studies.
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Affiliation(s)
- Anders Bergström
- Institute for Research on Cancer and Ageing, Nice (IRCAN), University of Nice, Nice, France
| | | | - Francisco Salinas
- Institute for Research on Cancer and Ageing, Nice (IRCAN), University of Nice, Nice, France
| | - Benjamin Barré
- Institute for Research on Cancer and Ageing, Nice (IRCAN), University of Nice, Nice, France
| | - Leopold Parts
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON, Canada
| | - Amin Zia
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
- Stanford Center for Genomics and Personalized Medicine, Stanford University School of Medicine
| | - Alex N. Nguyen Ba
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Alan M. Moses
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Edward J. Louis
- Centre of Genetic Architecture of Complex Traits, University of Leicester, Leicester, United Kingdom
| | - Ville Mustonen
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Jonas Warringer
- Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg, Sweden
| | - Richard Durbin
- The Wellcome Trust Sanger Institute, Cambridge, United Kingdom
| | - Gianni Liti
- Institute for Research on Cancer and Ageing, Nice (IRCAN), University of Nice, Nice, France
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112
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Abstract
Obtaining high-quality sequence continuity of complex regions of recent segmental duplication remains one of the major challenges of finishing genome assemblies. In the human and mouse genomes, this was achieved by targeting large-insert clones using costly and laborious capillary-based sequencing approaches. Sanger shotgun sequencing of clone inserts, however, has now been largely abandoned, leaving most of these regions unresolved in newer genome assemblies generated primarily by next-generation sequencing hybrid approaches. Here we show that it is possible to resolve regions that are complex in a genome-wide context but simple in isolation for a fraction of the time and cost of traditional methods using long-read single molecule, real-time (SMRT) sequencing and assembly technology from Pacific Biosciences (PacBio). We sequenced and assembled BAC clones corresponding to a 1.3-Mbp complex region of chromosome 17q21.31, demonstrating 99.994% identity to Sanger assemblies of the same clones. We targeted 44 differences using Illumina sequencing and find that PacBio and Sanger assemblies share a comparable number of validated variants, albeit with different sequence context biases. Finally, we targeted a poorly assembled 766-kbp duplicated region of the chimpanzee genome and resolved the structure and organization for a fraction of the cost and time of traditional finishing approaches. Our data suggest a straightforward path for upgrading genomes to a higher quality finished state.
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113
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Zhang Q. Using pseudogene database to identify lineage-specific genes and pseudogenes in humans and chimpanzees. ACTA ACUST UNITED AC 2014; 105:436-43. [PMID: 24399747 DOI: 10.1093/jhered/est097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
It has been revealed that gene content changes, or gene gains or losses, have played an important role in the evolution of modern humans. As one of the major players accounting for gene content changes, gene pseudogenization is abundant in mammalian genomes, and approximately 20000 pseudogenes have been identified in ape genomes. Therefore, it is an interesting question how to exploit rich information embedded in pseudogenes. Here, I present a bioinformatic pipeline that utilizes a pseudogene database to identify both lineage-specific genes and pseudogenes in humans and chimpanzees. I found 6 human-specific gene gains (HSGs), 1 chimpanzee-specific gene gain, and 4 chimpanzee-specific pseudogenes, most not discovered in previous studies. Further analysis showed that HSGs have been evolving under strong purifying selection and are broadly expressed, indicating strong functional constraint. This study demonstrates the usage of pseudogene information in comparative genomics and suggests that new genes during primate evolution may acquire essential functions in a short time. The pipeline developed here could also be applied to other species.
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Affiliation(s)
- Qu Zhang
- the Department of Human Evolutionary Biology, Graduate School of Art and Science, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138
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114
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Abstract
To understand the emergence of human higher cognition, we must understand its biological substrate--the cerebral cortex, which considers itself the crowning achievement of evolution. Here, we describe how advances in developmental neurobiology, coupled with those in genetics, including adaptive protein evolution via gene duplications and the emergence of novel regulatory elements, can provide insights into the evolutionary mechanisms culminating in the human cerebrum. Given that the massive expansion of the cortical surface and elaboration of its connections in humans originates from developmental events, understanding the genetic regulation of cell number, neuronal migration to proper layers, columns, and regions, and ultimately their differentiation into specific phenotypes, is critical. The pre- and postnatal environment also interacts with the cellular substrate to yield a basic network that is refined via selection and elimination of synaptic connections, a process that is prolonged in humans. This knowledge provides essential insight into the pathogenesis of human-specific neuropsychiatric disorders.
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Affiliation(s)
- Daniel H Geschwind
- Program in Neurogenetics, Department of Neurology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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