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Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence

The human and chimpanzee X chromosomes are less divergent than expected based on autosomal divergence. We study incomplete lineage sorting patterns between humans, chimpanzees and gorillas to show that this low divergence can be entirely explained by megabase-sized regions comprising one-third of th...

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Autores principales: Dutheil, Julien Y., Munch, Kasper, Nam, Kiwoong, Mailund, Thomas, Schierup, Mikkel H.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4537231/
https://www.ncbi.nlm.nih.gov/pubmed/26274919
http://dx.doi.org/10.1371/journal.pgen.1005451
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author Dutheil, Julien Y.
Munch, Kasper
Nam, Kiwoong
Mailund, Thomas
Schierup, Mikkel H.
author_facet Dutheil, Julien Y.
Munch, Kasper
Nam, Kiwoong
Mailund, Thomas
Schierup, Mikkel H.
author_sort Dutheil, Julien Y.
collection PubMed
description The human and chimpanzee X chromosomes are less divergent than expected based on autosomal divergence. We study incomplete lineage sorting patterns between humans, chimpanzees and gorillas to show that this low divergence can be entirely explained by megabase-sized regions comprising one-third of the X chromosome, where polymorphism in the human-chimpanzee ancestral species was severely reduced. We show that background selection can explain at most 10% of this reduction of diversity in the ancestor. Instead, we show that several strong selective sweeps in the ancestral species can explain it. We also report evidence of population specific sweeps in extant humans that overlap the regions of low diversity in the ancestral species. These regions further correspond to chromosomal sections shown to be devoid of Neanderthal introgression into modern humans. This suggests that the same X-linked regions that undergo selective sweeps are among the first to form reproductive barriers between diverging species. We hypothesize that meiotic drive is the underlying mechanism causing these two observations.
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spelling pubmed-45372312015-08-20 Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence Dutheil, Julien Y. Munch, Kasper Nam, Kiwoong Mailund, Thomas Schierup, Mikkel H. PLoS Genet Research Article The human and chimpanzee X chromosomes are less divergent than expected based on autosomal divergence. We study incomplete lineage sorting patterns between humans, chimpanzees and gorillas to show that this low divergence can be entirely explained by megabase-sized regions comprising one-third of the X chromosome, where polymorphism in the human-chimpanzee ancestral species was severely reduced. We show that background selection can explain at most 10% of this reduction of diversity in the ancestor. Instead, we show that several strong selective sweeps in the ancestral species can explain it. We also report evidence of population specific sweeps in extant humans that overlap the regions of low diversity in the ancestral species. These regions further correspond to chromosomal sections shown to be devoid of Neanderthal introgression into modern humans. This suggests that the same X-linked regions that undergo selective sweeps are among the first to form reproductive barriers between diverging species. We hypothesize that meiotic drive is the underlying mechanism causing these two observations. Public Library of Science 2015-08-14 /pmc/articles/PMC4537231/ /pubmed/26274919 http://dx.doi.org/10.1371/journal.pgen.1005451 Text en © 2015 Dutheil et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Dutheil, Julien Y.
Munch, Kasper
Nam, Kiwoong
Mailund, Thomas
Schierup, Mikkel H.
Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence
title Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence
title_full Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence
title_fullStr Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence
title_full_unstemmed Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence
title_short Strong Selective Sweeps on the X Chromosome in the Human-Chimpanzee Ancestor Explain Its Low Divergence
title_sort strong selective sweeps on the x chromosome in the human-chimpanzee ancestor explain its low divergence
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4537231/
https://www.ncbi.nlm.nih.gov/pubmed/26274919
http://dx.doi.org/10.1371/journal.pgen.1005451
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