Polygenic adaptation and convergent evolution across both growth and cardiac genetic pathways in African and Asian rainforest hunter-gatherers
Bergey et al (2018) Proceedings of the National Academy of Sciences. 115 (48):E11256-E11263. doi: 10.1073/pnas.1812135115
PDF available upon request.
Abstract: Different human populations facing similar environmental challenges have sometimes evolved convergent biological adaptations, for example, hypoxia resistance at high altitudes and depigmented skin in northern latitudes on separate continents. The “pygmy” phenotype (small adult body size), characteristic of hunter-gatherer populations inhabiting both African and Asian tropical rainforests, is often highlighted as another case of convergent adaptation in humans. However, the degree to which phenotypic convergence in this polygenic trait is due to convergent versus population-specific genetic changes is unknown. To address this question, we analyzed high-coverage sequence data from the protein-coding portion of the genomes of two pairs of populations: Batwa rainforest hunter-gatherers and neighboring Bakiga agriculturalists from Uganda and Andamanese rainforest hunter-gatherers and Brahmin agriculturalists from India. We observed signatures of convergent positive selection between the rainforest hunter-gatherers across the set of genes with “growth factor binding” functions (P<0.001). Unexpectedly, for the rainforest groups, we also observed convergent and population-specific signatures of positive selection in pathways related to cardiac development (e.g., “cardiac muscle tissue development”; P=0.001). We hypothesize that the growth hormone subresponsiveness likely underlying the adult small body-size phenotype may have led to compensatory changes in cardiac pathways, in which this hormone also plays an essential role. Importantly, in the agriculturalist populations, we did not observe similar patterns of positive selection on sets of genes associated with growth or cardiac development, indicating our results most likely reflect a history of convergent adaptation to the similar ecology of rainforests rather than a more general evolutionary pattern.
New paper! We find convergent selection on height and heart pathways in African and Asian rainforest hunter-gatherers with small adult body size. The latter could be cool compensatory evolution…? @PNASNews https://t.co/PLdrrfCrTT
— Christina Bergey (@bergeycm) November 12, 2018
Our new preprint, on work led by @bergeycm:
Polygenic adaptation & convergent evolution across both growth (expected) _and_ cardiac (unexpected; compensatory?) pathways in small-bodied African & Asian rainforest hunter-gatherers. https://t.co/n9LfmlaDD9 pic.twitter.com/vHCqsf9LGv
— George (PJ) Perry (@grg_perry) April 17, 2018
Currently satisfying my ? with #omics18 #aapa2018 where CM Bergey and @grg_perry are presenting on convergent selection on stature and cardiac pathways in African and Asian hunter-gatherers. Short phenotypes could have resulted in selection on pathways related to the heart. Or..
— Dr. Gwen Robbins Schug (@GRSchug) April 14, 2018
@bergeycm is presenting on convergent evolution of growth pathways – in multiple rainforest hunter-gatherer populations. #IntegratingAnthropology @AAAGenetics #AAPA2018 – preprint @biorxivpreprint https://t.co/vFemtZgRqA
— Omer Gokcumen (@gokcumen) April 14, 2018
Preprint available! We search for convergent polygenic selection in rainforest hunter-gatherer genomes and find some expected growth-related results and some unexpected heart-related results: https://t.co/OpdQyUCFJJ w/ @grg_perry @LB_Barreiro @GeneScientist17 @QuintanaMurci et al pic.twitter.com/7RtSzVn75D
— Christina Bergey (@bergeycm) April 13, 2018
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