Showing papers by "David Reich published in 2014"
Max Planck Society1, University of California, Berkeley2, Broad Institute3, Harvard University4, University of Washington5, National Institutes of Health6, University of California, Santa Cruz7, Ludwig Maximilian University of Munich8, Emory University9, Fondation Jean Dausset Centre d'Etude du Polymorphisme Humain10, Allen Institute for Brain Science11, Russian Academy of Sciences12, Howard Hughes Medical Institute13
TL;DR: It is shown that interbreeding, albeit of low magnitude, occurred among many hominin groups in the Late Pleistocene and a definitive list of substitutions that became fixed in modern humans after their separation from the ancestors of Neanderthals and Denisovans is established.
Abstract: We present a high-quality genome sequence of a Neanderthal woman from Siberia. We show that her parents were related at the level of half-siblings and that mating among close relatives was common among her recent ancestors. We also sequenced the genome of a Neanderthal from the Caucasus to low coverage. An analysis of the relationships and population history of available archaic genomes and 25 present-day human genomes shows that several gene flow events occurred among Neanderthals, Denisovans and early modern humans, possibly including gene flow into Denisovans from an unknown archaic group. Thus, interbreeding, albeit of low magnitude, occurred among many hominin groups in the Late Pleistocene. In addition, the high-quality Neanderthal genome allows us to establish a definitive list of substitutions that became fixed in modern humans after their separation from the ancestors of Neanderthals and Denisovans.
1,691 citations
Broad Institute1, Harvard University2, University of Tübingen3, Max Planck Society4, University of Mainz5, University of Washington6, University of California, Berkeley7, Massachusetts Institute of Technology8, Stockholm University9, University of Adelaide10, The Heritage Foundation11, National Museum of Natural History12, University of Edinburgh13, Sultan Qaboos University14, University of Costa Rica15, University of Antioquia16, Rambam Health Care Campus17, University of Pécs18, Al Akhawayn University19, Catholic University of the Sacred Heart20, University of Oxford21, Belgorod State University22, University of Toronto23, University of Buenos Aires24, University of Bern25, Russian Academy of Sciences26, Paul Sabatier University27, North-Eastern Federal University28, University of Chicago29, University of Arizona30, Stony Brook University31, University of Bergen32, Illumina33, Sofia Medical University34, Bashkir State University35, University of Cambridge36, Vilnius University37, Estonian Biocentre38, University of Strasbourg39, Amgen40, University College London41, Gladstone Institutes42, University of Tartu43, University of Oulu44, Muhimbili University of Health and Allied Sciences45, University of Palermo46, University of Tarapacá47, University of Chile48, Academy of Sciences of Uzbekistan49, Armenian National Academy of Sciences50, University of North Texas51, University of Santiago de Compostela52, University of Kharkiv53, Higher University of San Andrés54, Novosibirsk State University55, Leidos56, Lebanese American University57, University of Split58, University of Pennsylvania59, Banaras Hindu University60, Centre for Cellular and Molecular Biology61, Estonian Academy of Sciences62, Pompeu Fabra University63, Howard Hughes Medical Institute64
TL;DR: It is shown that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians; and early European farmers, who were mainly of Near Eastern origin but also harboured west Europeanhunter-gatherer related ancestry.
Abstract: We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had ∼44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.
1,077 citations
Chinese Academy of Sciences1, Harvard University2, Columbia University3, University of California, Berkeley4, Russian Academy of Sciences5, Emory University6, Max Planck Society7, University of California, Davis8, University of Cape Town9, University of British Columbia10, University of Oxford11, Howard Hughes Medical Institute12
TL;DR: The high-quality genome sequence of a ∼45,000-year-old modern human male from Siberia derives from a population that lived before—or simultaneously with—the separation of the populations in western and eastern Eurasia and carries a similar amount of Neanderthal ancestry as present-day Eurasians.
Abstract: We present the high-quality genome sequence of a 45,000-year-old modern human male from Siberia. This individual derives from a population that lived before—or simultaneously with—the separation of the populations in western and eastern Eurasia and carries a similar amount of Neanderthal ancestry as present-day Eurasians. However, the genomic segments of Neanderthal ancestry are substantially longer than those observed in present-day individuals, indicating that Neanderthal gene flow into the ancestors of this individual occurred 7,000–13,000 years before he lived. We estimate an autosomal mutation rate of 0.4 3 10 29 to 0.6 3 10 29 per site per year, a Y chromosomal mutation rate of 0.7 3 10 29 to 0.9 3 10 29 per site per year based on the additional substitutions that have occurred in present-day nonAfricans compared to this genome, and a mitochondrial mutation rate of 1.8 3 10 28 to 3.2 3 10 28 per site per year based on the age of the bone.
814 citations
TL;DR: The results suggest that part of the explanation for genomic regions of reduced Neanderthal ancestry is Neanderthal alleles that caused decreased fertility in males when moved to a modern human genetic background.
Abstract: Genomic studies have shown that Neanderthals interbred with modern humans, and that non-Africans today are the products of this mixture. The antiquity of Neanderthal gene flow into modern humans means that genomic regions that derive from Neanderthals in any one human today are usually less than a hundred kilobases in size. However, Neanderthal haplotypes are also distinctive enough that several studies have been able to detect Neanderthal ancestry at specific loci. We systematically infer Neanderthal haplotypes in the genomes of 1,004 present-day humans. Regions that harbour a high frequency of Neanderthal alleles are enriched for genes affecting keratin filaments, suggesting that Neanderthal alleles may have helped modern humans to adapt to non-African environments. We identify multiple Neanderthal-derived alleles that confer risk for disease, suggesting that Neanderthal alleles continue to shape human biology. An unexpected finding is that regions with reduced Neanderthal ancestry are enriched in genes, implying selection to remove genetic material derived from Neanderthals. Genes that are more highly expressed in testes than in any other tissue are especially reduced in Neanderthal ancestry, and there is an approximately fivefold reduction of Neanderthal ancestry on the X chromosome, which is known from studies of diverse species to be especially dense in male hybrid sterility genes. These results suggest that part of the explanation for genomic regions of reduced Neanderthal ancestry is Neanderthal alleles that caused decreased fertility in males when moved to a modern human genetic background.
810 citations
Harvard University1, Broad Institute2, University of Tübingen3, Max Planck Society4, University of Mainz5, University of Washington6, University of California, Berkeley7, Massachusetts Institute of Technology8, Stockholm University9, University of Adelaide10, The Heritage Foundation11, National Museum of Natural History12, Sultan Qaboos University13, University of Edinburgh14, University of Costa Rica15, University of Antioquia16, Rambam Health Care Campus17, University of Pécs18, Al Akhawayn University19, Catholic University of the Sacred Heart20, University of Oxford21, Belgorod State University22, University of Toronto23, University of Buenos Aires24, University of Bern25, Russian Academy of Sciences26, Paul Sabatier University27, North-Eastern Federal University28, University of Chicago29, University of Arizona30, Stony Brook University31, University of Bergen32, Illumina33, Sofia Medical University34, Bashkir State University35, University of Cambridge36, Vilnius University37, Estonian Biocentre38, University of Strasbourg39, University College London40, Amgen41, Gladstone Institutes42, University of Tartu43, University of Oulu44, Muhimbili University of Health and Allied Sciences45, University of Palermo46, University of Chile47, University of Tarapacá48, Academy of Sciences of Uzbekistan49, Armenian National Academy of Sciences50, University of North Texas51, University of Santiago de Compostela52, University of Kharkiv53, Higher University of San Andrés54, Novosibirsk State University55, Leidos56, Lebanese American University57, University of Split58, University of Pennsylvania59, Banaras Hindu University60, Centre for Cellular and Molecular Biology61, Estonian Academy of Sciences62, Pompeu Fabra University63, Howard Hughes Medical Institute64
TL;DR: The authors showed that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, ancient north Eurasians related to Upper Palaeolithic Siberians, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunters-gatherer related ancestry.
Abstract: We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these populations' deep relationships and show that early European farmers had ∼44% ancestry from a 'basal Eurasian' population that split before the diversification of other non-African lineages.
442 citations
Broad Institute1, Harvard University2, Universidad Autónoma Metropolitana3, National Autonomous University of Mexico4, Universidad Autónoma de Nuevo León5, Massachusetts Institute of Technology6, University of Southern California7, Mexican Social Security Institute8, University of Hawaii at Manoa9, Max Planck Society10, University of Minnesota11, University of California, San Francisco12, National University of Singapore13, University of Oxford14, University of Michigan15, Yeshiva University16, Texas Biomedical Research Institute17, Wake Forest University18, National Health Service19, Imperial College London20, Hallym University21, Wolfson Medical Center22, Hebrew University of Jerusalem23, University of Texas Health Science Center at Houston24, University of Eastern Finland25, Agency for Science, Technology and Research26, University of Mississippi27, University of Texas Health Science Center at San Antonio28
TL;DR: Analysis in Mexican and Latin American individuals identified SLC16A11 as a novel candidate gene for type 2 diabetes with a possible role in triacylglycerol metabolism and an archaic genome sequence indicated that the risk haplotype introgressed into modern humans via admixture with Neanderthals.
Abstract: Performing genetic studies in multiple human populations can identify disease risk alleles that are common in one population but rare in others, with the potential to illuminate pathophysiology, health disparities, and the population genetic origins of disease alleles. Here we analysed 9.2 million single nucleotide polymorphisms (SNPs) in each of 8,214 Mexicans and other Latin Americans: 3,848 with type 2 diabetes and 4,366 non-diabetic controls. In addition to replicating previous findings, we identified a novel locus associated with type 2 diabetes at genome-wide significance spanning the solute carriers SLC16A11 and SLC16A13 (P = 3.9 × 10(-13); odds ratio (OR) = 1.29). The association was stronger in younger, leaner people with type 2 diabetes, and replicated in independent samples (P = 1.1 × 10(-4); OR = 1.20). The risk haplotype carries four amino acid substitutions, all in SLC16A11; it is present at ~50% frequency in Native American samples and ~10% in east Asian, but is rare in European and African samples. Analysis of an archaic genome sequence indicated that the risk haplotype introgressed into modern humans via admixture with Neanderthals. The SLC16A11 messenger RNA is expressed in liver, and V5-tagged SLC16A11 protein localizes to the endoplasmic reticulum. Expression of SLC16A11 in heterologous cells alters lipid metabolism, most notably causing an increase in intracellular triacylglycerol levels. Despite type 2 diabetes having been well studied by genome-wide association studies in other populations, analysis in Mexican and Latin American individuals identified SLC16A11 as a novel candidate gene for type 2 diabetes with a possible role in triacylglycerol metabolism.
431 citations
Oregon Health & Science University1, Baylor College of Medicine2, University of Arizona3, Stony Brook University4, Pompeu Fabra University5, Howard Hughes Medical Institute6, University of Washington7, University College London8, German Primate Center9, University of Bari10, Louisiana State University11, University of Toulouse12, Johns Hopkins University13, University of Utah14, Texas A&M University15, Babeș-Bolyai University16, Children's Hospital Oakland Research Institute17, University of Colorado Denver18, Max Delbrück Center for Molecular Medicine19, University of Barcelona20, Indiana University21, Washington University in St. Louis22, Institute for Systems Biology23, Pennsylvania State University24, University of Pittsburgh25, Harvard University26, Stanford University27, University of Cambridge28, University of California, San Francisco29, Paul Ehrlich Institute30, Gibbon Conservation Center31, University of Chicago32, Broad Institute33
TL;DR: The assembly and analysis of a northern white-cheeked gibbon genome is presented and the propensity for a gibbon-specific retrotransposon (LAVA) to insert into chromosome segregation genes and alter transcription by providing a premature termination site is described, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage.
Abstract: Gibbons are small arboreal apes that display an accelerated rate of evolutionary chromosomal rearrangement and occupy a key node in the primate phylogeny between Old World monkeys and great apes. Here we present the assembly and analysis of a northern white-cheeked gibbon (Nomascus leucogenys) genome. We describe the propensity for a gibbon-specific retrotransposon (LAVA) to insert into chromosome segregation genes and alter transcription by providing a premature termination site, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage. We further show that the gibbon genera (Nomascus, Hylobates, Hoolock and Symphalangus) experienced a near-instantaneous radiation ~5 million years ago, coincident with major geographical changes in southeast Asia that caused cycles of habitat compression and expansion. Finally, we identify signatures of positive selection in genes important for forelimb development (TBX5) and connective tissues (COL1A1) that may have been involved in the adaptation of gibbons to their arboreal habitat.
318 citations
TL;DR: Genome-wide genetic data is used to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants) and that west Eurasian ancestry entered southern Africa indirectly through eastern Africa.
Abstract: The history of southern Africa involved interactions between indigenous hunter–gatherers and a range of populations that moved into the region. Here we use genome-wide genetic data to show that there are at least two admixture events in the history of Khoisan populations (southern African hunter–gatherers and pastoralists who speak non-Bantu languages with click consonants). One involved populations related to Niger–Congo-speaking African populations, and the other introduced ancestry most closely related to west Eurasian (European or Middle Eastern) populations. We date this latter admixture event to ∼900–1,800 y ago and show that it had the largest demographic impact in Khoisan populations that speak Khoe–Kwadi languages. A similar signal of west Eurasian ancestry is present throughout eastern Africa. In particular, we also find evidence for two admixture events in the history of Kenyan, Tanzanian, and Ethiopian populations, the earlier of which involved populations related to west Eurasians and which we date to ∼2,700–3,300 y ago. We reconstruct the allele frequencies of the putative west Eurasian population in eastern Africa and show that this population is a good proxy for the west Eurasian ancestry in southern Africa. The most parsimonious explanation for these findings is that west Eurasian ancestry entered southern Africa indirectly through eastern Africa.
256 citations
TL;DR: It is argued that it is time to critically reevaluate current models of the peopling of the globe, as well as the importance of natural selection in determining the geographic distribution of phenotypes.
189 citations
TL;DR: It is shown that all sampled Austronesian groups harbour ancestry that is more closely related to aboriginal Taiwanese than to any present-day mainland population, suggesting that either there was once a substantial Austro-Asiatic presence in Island Southeast Asia, orAustronesian speakers migrated to and through the mainland, admixing there before continuing to western Indonesia.
Abstract: Austronesian languages are spread across half the globe, from Easter Island to Madagascar. Evidence from linguistics and archaeology indicates that the ‘Austronesian expansion,’ which began 4,000–5,000 years ago, likely had roots in Taiwan, but the ancestry of present-day Austronesian-speaking populations remains controversial. Here, we analyse genome-wide data from 56 populations using new methods for tracing ancestral gene flow, focusing primarily on Island Southeast Asia. We show that all sampled Austronesian groups harbour ancestry that is more closely related to aboriginal Taiwanese than to any present-day mainland population. Surprisingly, western Island Southeast Asian populations have also inherited ancestry from a source nested within the variation of present-day populations speaking Austro-Asiatic languages, which have historically been nearly exclusive to the mainland. Thus, either there was once a substantial Austro-Asiatic presence in Island Southeast Asia, or Austronesian speakers migrated to and through the mainland, admixing there before continuing to western Indonesia.
153 citations
Harvard University1, Broad Institute2, University of Tübingen3, Max Planck Society4, University of Mainz5, University of Washington6, University of California, Berkeley7, Massachusetts Institute of Technology8, Stockholm University9, University of Adelaide10, The Heritage Foundation11, National Museum of Natural History12, American Museum of Natural History13, University of Edinburgh14, National Scientific and Technical Research Council15, University of Costa Rica16, University of Antioquia17, Rambam Health Care Campus18, University of Pécs19, Al Akhawayn University20, Catholic University of the Sacred Heart21, University of Oxford22, Belgorod State University23, University of Toronto24, University of Buenos Aires25, Russian Academy26, University of Bern27, Paul Sabatier University28, North-Eastern Federal University29, University of Chicago30, Russian Academy of Sciences31, University of Arizona32, Stony Brook University33, University of Bergen34, Illumina35, Sofia Medical University36, University of Illinois at Chicago37, University of Cambridge38, Vilnius University39, Estonian Biocentre40, University of Strasbourg41, Amgen42, Gladstone Institutes43, University of Tartu44, University of Oulu45, Muhimbili University of Health and Allied Sciences46, University of Palermo47, University of Tarapacá48, Academy of Sciences of Uzbekistan49, University of Helsinki50, University of Santiago de Compostela51, University of Kharkiv52, Higher University of San Andrés53, Leidos54, Armenian National Academy of Sciences55, Lebanese American University56, University of Split57, University College London58, University of Pennsylvania59, Centre for Cellular and Molecular Biology60, Pompeu Fabra University61
TL;DR: It is shown that the great majority of present-day Europeans derive from at least three highly differentiated populations: West European Hunter-Gatherers (WHG), who contributed ancestry to all Europeans but not to Near Easterners; Ancient North Eurasians (ANE); and Early European Farmers (EEF), who were mainly of Near Eastern origin but also harbored WHG-related ancestry.
Abstract: We sequenced genomes from a ~7,000 year old early farmer from Stuttgart in Germany, an ~8,000 year old hunter-gatherer from Luxembourg, and seven ~8,000 year old hunter-gatherers from southern Sweden. We analyzed these data together with other ancient genomes and 2,345 contemporary humans to show that the great majority of present-day Europeans derive from at least three highly differentiated populations: West European Hunter-Gatherers (WHG), who contributed ancestry to all Europeans but not to Near Easterners; Ancient North Eurasians (ANE), who were most closely related to Upper Paleolithic Siberians and contributed to both Europeans and Near Easterners; and Early European Farmers (EEF), who were mainly of Near Eastern origin but also harbored WHG-related ancestry. We model these populations' deep relationships and show that EEF had ~44% ancestry from a "Basal Eurasian" lineage that split prior to the diversification of all other non-African lineages.
University of California, San Francisco1, University of California, Los Angeles2, Harvard University3, Massachusetts Institute of Technology4, University of Southern California5, Stanford University6, National Institutes of Health7, Vanderbilt University8, University of North Carolina at Chapel Hill9, University of the West Indies10, Cancer Prevention Institute of California11, Johns Hopkins University12, University of Illinois at Chicago13, Cleveland Clinic14, Howard Hughes Medical Institute15, Henry Ford Health System16, Fred Hutchinson Cancer Research Center17, American Cancer Society18, University of Texas MD Anderson Cancer Center19, Wake Forest University20, University of Mississippi21, University of Washington22
TL;DR: This work estimates h2 from unrelated individuals in admixed populations by first estimating the heritability explained by local ancestry (h2γ), and shows that h2γ = 2FSTCθ(1 − θ)h2, where FSTC measures frequency differences between populations at causal loci and θ is the genome-wide ancestry proportion.
Abstract: Despite recent progress on estimating the heritability explained by genotyped SNPs (h(2)g), a large gap between h(2)g and estimates of total narrow-sense heritability (h(2)) remains. Explanations for this gap include rare variants or upward bias in family-based estimates of h(2) due to shared environment or epistasis. We estimate h(2) from unrelated individuals in admixed populations by first estimating the heritability explained by local ancestry (h(2)γ). We show that h(2)γ = 2FSTCθ(1 - θ)h(2), where FSTC measures frequency differences between populations at causal loci and θ is the genome-wide ancestry proportion. Our approach is not susceptible to biases caused by epistasis or shared environment. We applied this approach to the analysis of 13 phenotypes in 21,497 African-American individuals from 3 cohorts. For height and body mass index (BMI), we obtained h(2) estimates of 0.55 ± 0.09 and 0.23 ± 0.06, respectively, which are larger than estimates of h(2)g in these and other data but smaller than family-based estimates of h(2).
Harvard University1, Broad Institute2, Vanderbilt University3, Roswell Park Cancer Institute4, Dartmouth College5, Rutgers University6, National Institutes of Health7, City of Hope National Medical Center8, Wayne State University9, University of Southern California10, American Cancer Society11, Johns Hopkins University12, Cancer Prevention Institute of California13, Stanford University14, University of Illinois at Chicago15, University of Texas MD Anderson Cancer Center16, University of North Carolina at Chapel Hill17, Northwestern University18, Henry Ford Health System19, University of Miami20, University of California, San Francisco21
TL;DR: Scanning the genomes of 29,141 African Americans and failed to find any genome-wide-significant deviations in local ancestry, indicating no evidence of selection influencing ancestry after admixture.
Abstract: The extent of recent selection in admixed populations is currently an unresolved question. We scanned the genomes of 29,141 African Americans and failed to find any genome-wide-significant deviations in local ancestry, indicating no evidence of selection influencing ancestry after admixture. A recent analysis of data from 1,890 African Americans reported that there was evidence of selection in African Americans after their ancestors left Africa, both before and after admixture. Selection after admixture was reported on the basis of deviations in local ancestry, and selection before admixture was reported on the basis of allele-frequency differences between African Americans and African populations. The local-ancestry deviations reported by the previous study did not replicate in our very large sample, and we show that such deviations were expected purely by chance, given the number of hypotheses tested. We further show that the previous study’s conclusion of selection in African Americans before admixture is also subject to doubt. This is because the FST statistics they used were inflated and because true signals of unusual allele-frequency differences between African Americans and African populations would be best explained by selection that occurred in Africa prior to migration to the Americas.
TL;DR: It is shown that all sampled Austronesian groups harbor ancestry that is more closely related to aboriginal Taiwanese than to any present-day mainland population, suggesting that either there was once a substantial Austro-Asiatic presence in Island Southeast Asia, or Austronesians migrated to and through the mainland, admixing there before continuing to western Indonesia.
Abstract: Austronesian languages are spread across half the globe, from Easter Island to Madagascar. Evidence from linguistics and archaeology indicates that the "Austronesian expansion," which began 4-5 thousand years ago, likely had roots in Taiwan, but the ancestry of present-day Austronesian-speaking populations remains controversial. Here, focusing primarily on Island Southeast Asia, we analyze genome-wide data from 56 populations using new methods for tracing ancestral gene flow. We show that all sampled Austronesian groups harbor ancestry that is more closely related to aboriginal Taiwanese than to any present-day mainland population. Surprisingly, western Island Southeast Asian populations have also inherited ancestry from a source nested within the variation of present-day populations speaking Austro-Asiatic languages, which have historically been nearly exclusive to the mainland. Thus, either there was once a substantial Austro-Asiatic presence in Island Southeast Asia, or Austronesian speakers migrated to and through the mainland, admixing there before continuing to western Indonesia.
TL;DR: The first genome-wide study of NCO events in humans is reported, using SNP array data from 98 meioses to identify 103 sites affected by NCO, which shows strong allelic bias at heterozygous AT/GC SNPs, with 68% (58–78%) transmitting GC alleles.
Abstract: Although the past decade has seen tremendous progress in our understanding of fine-scale recombination, little is known about non-crossover (or "gene conversion") resolutions. We report the first genome-wide study of non-crossover gene conversion events in humans. Using SNP array data from 94 meioses, we identified 107 sites affected by non-crossover events, of which 51/53 were confirmed in sequence data. Our results suggest that a site is involved in a non-crossover event at a rate of 6.7 × 10-6/bp/generation, consistent with results from sperm-typing studies. Observed non-crossover events show strong allelic bias, with 70% (61--79%) of events transmitting GC alleles (P=7.9 × 10-5), and have tracts lengths that vary over more than an order of magnitude. Strikingly, in 4 of 15 regions with available resequencing data, multiple (~2--4) distinct non-crossover events cluster within ~20--30 kb. This pattern has not been reported previously in mammals and is inconsistent with canonical models of double strand break repair.
TL;DR: This study studied the genetic ancestry of 5,269 self-described African Americans, 8,663 Latinos, and 148,789 European Americans who are 23andMe customers and shows that regional ancestry differences reflect historical events such as early Spanish colonization, waves of immigration from many regions of Europe, and forced relocation of Native Americans within the US.
Abstract: Over the past 500 years, North America has been the site of ongoing mixing of Native Americans, European settlers, and Africans brought largely by the Trans-Atlantic slave trade, shaping the early history of what became the United States. We studied the genetic ancestry of 5,269 self-described African Americans, 8,663 Latinos, and 148,789 European Americans who are 23andMe customers and show that the legacy of these historical interactions is visible in the genetic ancestry of present-day Americans. We document pervasive mixed ancestry and asymmetrical male and female ancestry contributions in all groups studied. We show that regional ancestry differences reflect historical events, such as early Spanish colonization, waves of immigration from many regions of Europe, and forced relocation of Native Americans within the US. This study sheds light on the fine-scale differences in ancestry within and across the United States, and informs our understanding of the relationship between racial and ethnic identities and genetic ancestry.
TL;DR: It is argued that it is time to critically re-evaluate current views of the peopling of the globe and the importance of natural selection in determining the geographic distribution of phenotypes and the transformative potential of ancient DNA is highlighted.
Abstract: Genetic information contains a record of the history of our species, and technological advances have transformed our ability to access this record. Many studies have used genome-wide data from populations today to learn about the peopling of the globe and subsequent adaptation to local conditions. Implicit in this research is the assumption that the geographic locations of people today are informative about the geographic locations of their ancestors in the distant past. However, it is now clear that long-range migration, admixture and population replacement have been the rule rather than the exception in human history. In light of this, we argue that it is time to critically re-evaluate current views of the peopling of the globe and the importance of natural selection in determining the geographic distribution of phenotypes. We specifically highlight the transformative potential of ancient DNA. By accessing the genetic make-up of populations living at archaeologically-known times and places, ancient DNA makes it possible to directly track migrations and responses to natural selection.
TL;DR: This article measured the per-genome accumulation of deleterious mutations across diverse humans and found that archaic Denisovans accumulated non-synonymous mutations at a higher rate than modern humans, consistent with the longer separation time of modern and archaic humans.
Abstract: Non-African populations have experienced major bottlenecks in the time since their split from West Africans, which has led to the hypothesis that natural selection to remove weakly deleterious mutations may have been less effective in non-Africans. To directly test this hypothesis, we measure the per-genome accumulation of deleterious mutations across diverse humans. We fail to detect any significant differences, but find that archaic Denisovans accumulated non-synonymous mutations at a higher rate than modern humans, consistent with the longer separation time of modern and archaic humans. We also revisit the empirical patterns that have been interpreted as evidence for less effective removal of deleterious mutations in non-Africans than in West Africans, and show they are not driven by differences in selection after population separation, but by neutral evolution.
TL;DR: This test uses explicitly non-equilibrium demographic differences between populations to infer the mode of selection by analyzing the transient response to a population bottleneck and subsequent re-expansion and qualitatively distinguish between alleles under additive and recessive selection.
Abstract: Here we present the first genome wide statistical test for recessive selection. This test uses explicitly non-equilibrium demographic differences between populations to infer the mode of selection. By analyzing the transient response to a population bottleneck and subsequent re-expansion, we qualitatively distinguish between alleles under additive and recessive selection. We analyze the response of the average number of deleterious mutations per haploid individual and describe time dependence of this quantity. We introduce a statistic, BR, to compare the number of mutations in different populations and detail its functional dependence on the strength of selection and the intensity of the population bottleneck. This test can be used to detect the predominant mode of selection on the genome wide or regional level, as well as among a sufficiently large set of medically or functionally relevant alleles.
01 Jan 2014
TL;DR: This paper aims to demonstrate the efforts towards in-situ applicability of EMMARM, as to provide real-time information about the response of the immune system to EMTs.
Abstract: 1 Department of Genetics, Harvard Medical School 2 Broad Institute 3 Department of Computer Science and Mathematics and AI Laboratory, MIT 4 Department of Evolutionary Genetics, MPI for Evolutionary Anthropology 5 Laboratoire Dynamique du Langage, UMR5596, CNRS and Universite Lyon Lumiere 2 6 Howard Hughes Medical Institute, Harvard Medical School 7 Current address: New York Genome Center † To whom correspondence should be addressed: jkpickrell@nygenome.org,
Posted Content•
TL;DR: The empirical patterns that have been interpreted as evidence for less effective removal of deleterious mutations in non-Africans than in West Africans are revisited, and show they are not driven by differences in selection after population separation, but by neutral evolution.
Abstract: Non-African populations have experienced major bottlenecks in the time since their split from West Africans, which has led to the hypothesis that natural selection to remove weakly deleterious mutations may have been less effective in non-Africans. To directly test this hypothesis, we measure the per-genome accumulation of deleterious mutations across diverse humans. We fail to detect any significant differences, but find that archaic Denisovans accumulated non-synonymous mutations at a higher rate than modern humans, consistent with the longer separation time of modern and archaic humans. We also revisit the empirical patterns that have been interpreted as evidence for less effective removal of deleterious mutations in non-Africans than in West Africans, and show they are not driven by differences in selection after population separation, but by neutral evolution.