第1477回生物科学セミナー
Inferring signatures of intermixing and adaptation in human populations using genetic variation data
Dr. Garrett Hellenthal（UCL Division of Biosciences）
2023年12月12日(火) 16:50-18:35 理学部2号館223号室及びZoom
I describe statistical techniques developed with colleagues that leverage genetic variation data to (1) cluster individuals into genetically homogeneous groups and (2) identify and date past events when different human populations intermixed. Applying our methods to large-scale genome-wide data resources from >100 world-wide populations, we describe fine-scale genetic structure within countries that is associated with geography and past history. We also infer dozens of intermixing episodes occurring within the last 4,000 years among geographically separated human groups. Many of these events align with well-attested historical empires and migrations, though I demonstrate how such genetics-based inference can also unearth previously unknown interactions and help resolve archaeological/anthropological controversies.
Furthermore, I describe a new technique that uses these intermixing signatures to identify genetic variants that have facilitated humans' ability to adapt to new environments, and determine whether this adaptation occurred before or after the intermixing. In an analysis of ~4,000 Latin Americans, we infer adaptation signatures at different timescales, incorporating results from recent expression quantitative loci (eQTL) and genome-wide association (GWAS) studies to link these signatures to immune and metabolic phenotypes. Examples include evidence of recent adaptive responses plausibly related to infectious disease pressures brought by European contact, and of older adaptive responses to pregnancy complications associated with living at high elevation.
References
Bird et al 2023, Dense sampling of ethnic groups within African countries reveals fine-scale genetic structure and extensive historical admixture, Sci Advances 9(13):eabq2616.
Mendoza-Revilla et al 2022, Disentangling signatures of selection before and after European colonization in Latin Americans, Mol Biol Evol 39(4):msac076.
Chacon-Duque et al 2018, Latin Americans show wide-spread Converso ancestry and the imprint of local Native ancestry on physical appearance, Nature Commun 9(1):5388.
Leslie et al 2015, The fine scale genetic structure of the British population, Nature 519:309-314.
Hellenthal et al 2014, A genetic atlas of human admixture history, Science 343:747-51.
Lawson et al 2012, Inference of population structure using dense haplotype data, PLoS Genetics 8(1):e1002453.
Responsible： Laboratory of Genome Anthropology, School of Science, The University of Tokyo.
