Continental-scale genomic analysis suggests shared post-admixture adaptation in the Americas
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Oxford University Press
Date
2021-07-01Referencia bibliográfica
Linda Ongaro... [et al.]. Continental-scale genomic analysis suggests shared post-admixture adaptation in the Americas, Human Molecular Genetics, Volume 30, Issue 22, 15 November 2021, Pages 2123–2134, [https://doi.org/10.1093/hmg/ddab177]
Sponsorship
European Commission 2014-2020.4.01.16-0030 2014-2020.4.01.16-0271 2014-2020.4.01.16-0125 2014-2020.4.01.16-0024 MOBEC008; Estonian Research Council grant PUT PRG243; institutional research funding IUT of the Estonian Ministry of Education and Research IUT24-1; European Union through Horizon 2020 grant 810645Abstract
American populations are one of the most interesting examples of recently admixed groups, where ancestral components
from three major continental human groups (Africans, Eurasians and Native Americans) have admixed within the last 15
generations. Recently, several genetic surveys focusing on thousands of individuals shed light on the geography, chronology
and relevance of these events. However, even though gene f low could drive adaptive evolution, it is unclear whether and
how natural selection acted on the resulting genetic variation in the Americas. In this study, we analysed the patterns of
local ancestry of genomic fragments in genome-wide data for ∼6000 admixed individuals from 10 American countries. In
doing so, we identified regions characterized by a divergent ancestry profile (DAP), in which a significant over or under
ancestral representation is evident. Our results highlighted a series of genomic regions with DAPs associated with immune
system response and relevant medical traits, with the longest DAP region encompassing the human leukocyte antigen
locus. Furthermore, we found that DAP regions are enriched in genes linked to cancer-related traits and autoimmune
diseases. Then, analysing the biological impact of these regions, we showed that natural selection could have acted preferentially towards variants located in coding and non-coding transcripts and characterized by a high deleteriousness
score. Taken together, our analyses suggest that shared patterns of post admixture adaptation occurred at a continental
scale in the Americas, affecting more often functional and impactful genomic variants.