Formulating a Historical and Demographic Model of Recent Human Evolution Based on Resequencing Data from Noncoding Regions |
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Authors: | Guillaume Laval Etienne Patin Luis B Barreiro Lluís Quintana-Murci |
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Institution: | 1. Human Evolutionary Genetics, Institut Pasteur, Paris, France.; 2. Centre National de la Recherche Scientifique, URA3012, Paris, France.;State University of New York College at Oneonta, United States of America |
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Abstract: | BackgroundEstimating the historical and demographic parameters that characterize modern human populations is a fundamental part of reconstructing the recent history of our species. In addition, the development of a model of human evolution that can best explain neutral genetic diversity is required to identify confidently regions of the human genome that have been targeted by natural selection.Methodology/Principal FindingsWe have resequenced 20 independent noncoding autosomal regions dispersed throughout the genome in 213 individuals from different continental populations, corresponding to a total of ∼6 Mb of diploid resequencing data. We used these data to explore and co-estimate an extensive range of historical and demographic parameters with a statistical framework that combines the evaluation of multiple models of human evolution via a best-fit approach, followed by an Approximate Bayesian Computation (ABC) analysis. From a methodological standpoint, evaluating the accuracy of the parameter co-estimation allowed us to identify the most accurate set of statistics to be used for the estimation of each of the different historical and demographic parameters characterizing recent human evolution.Conclusions/SignificanceOur results support a model in which modern humans left Africa through a single major dispersal event occurring ∼60,000 years ago, corresponding to a drastic reduction of ∼5 times the effective population size of the ancestral African population of ∼13,800 individuals. Subsequently, the ancestors of modern Europeans and East Asians diverged much later, ∼22,500 years ago, from the population of ancestral migrants. This late diversification of Eurasians after the African exodus points to the occurrence of a long maturation phase in which the ancestral Eurasian population was not yet diversified. |
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