The Strength of Selection against Neanderthal Introgression.
Hybridization between humans and Neanderthals has resulted in a low level of Neanderthal ancestry scattered across the genomes of many modern-day humans. After hybridization, on average, selection appears to have removed Neanderthal alleles from the human population. Quantifying the strength and cau...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2016-11-01
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| Series: | PLoS Genetics |
| Online Access: | http://europepmc.org/articles/PMC5100956?pdf=render |
| _version_ | 1818194310294667264 |
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| author | Ivan Juric Simon Aeschbacher Graham Coop |
| author_facet | Ivan Juric Simon Aeschbacher Graham Coop |
| author_sort | Ivan Juric |
| collection | DOAJ |
| description | Hybridization between humans and Neanderthals has resulted in a low level of Neanderthal ancestry scattered across the genomes of many modern-day humans. After hybridization, on average, selection appears to have removed Neanderthal alleles from the human population. Quantifying the strength and causes of this selection against Neanderthal ancestry is key to understanding our relationship to Neanderthals and, more broadly, how populations remain distinct after secondary contact. Here, we develop a novel method for estimating the genome-wide average strength of selection and the density of selected sites using estimates of Neanderthal allele frequency along the genomes of modern-day humans. We confirm that East Asians had somewhat higher initial levels of Neanderthal ancestry than Europeans even after accounting for selection. We find that the bulk of purifying selection against Neanderthal ancestry is best understood as acting on many weakly deleterious alleles. We propose that the majority of these alleles were effectively neutral-and segregating at high frequency-in Neanderthals, but became selected against after entering human populations of much larger effective size. While individually of small effect, these alleles potentially imposed a heavy genetic load on the early-generation human-Neanderthal hybrids. This work suggests that differences in effective population size may play a far more important role in shaping levels of introgression than previously thought. |
| first_indexed | 2024-12-12T01:00:15Z |
| format | Article |
| id | doaj.art-7c0b9ad26aee4810b0373b387946ab03 |
| institution | Directory Open Access Journal |
| issn | 1553-7390 1553-7404 |
| language | English |
| last_indexed | 2024-12-12T01:00:15Z |
| publishDate | 2016-11-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS Genetics |
| spelling | doaj.art-7c0b9ad26aee4810b0373b387946ab032022-12-22T00:43:44ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042016-11-011211e100634010.1371/journal.pgen.1006340The Strength of Selection against Neanderthal Introgression.Ivan JuricSimon AeschbacherGraham CoopHybridization between humans and Neanderthals has resulted in a low level of Neanderthal ancestry scattered across the genomes of many modern-day humans. After hybridization, on average, selection appears to have removed Neanderthal alleles from the human population. Quantifying the strength and causes of this selection against Neanderthal ancestry is key to understanding our relationship to Neanderthals and, more broadly, how populations remain distinct after secondary contact. Here, we develop a novel method for estimating the genome-wide average strength of selection and the density of selected sites using estimates of Neanderthal allele frequency along the genomes of modern-day humans. We confirm that East Asians had somewhat higher initial levels of Neanderthal ancestry than Europeans even after accounting for selection. We find that the bulk of purifying selection against Neanderthal ancestry is best understood as acting on many weakly deleterious alleles. We propose that the majority of these alleles were effectively neutral-and segregating at high frequency-in Neanderthals, but became selected against after entering human populations of much larger effective size. While individually of small effect, these alleles potentially imposed a heavy genetic load on the early-generation human-Neanderthal hybrids. This work suggests that differences in effective population size may play a far more important role in shaping levels of introgression than previously thought.http://europepmc.org/articles/PMC5100956?pdf=render |
| spellingShingle | Ivan Juric Simon Aeschbacher Graham Coop The Strength of Selection against Neanderthal Introgression. PLoS Genetics |
| title | The Strength of Selection against Neanderthal Introgression. |
| title_full | The Strength of Selection against Neanderthal Introgression. |
| title_fullStr | The Strength of Selection against Neanderthal Introgression. |
| title_full_unstemmed | The Strength of Selection against Neanderthal Introgression. |
| title_short | The Strength of Selection against Neanderthal Introgression. |
| title_sort | strength of selection against neanderthal introgression |
| url | http://europepmc.org/articles/PMC5100956?pdf=render |
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