TY - JOUR
T1 - Polygenic adaptation and convergent evolution on growth and cardiac genetic pathways in African and Asian rainforest hunter-gatherers
AU - Bergey, Christina M.
AU - Lopez, Marie
AU - Harrison, Genelle F.
AU - Patin, Etienne
AU - Cohen, Jacob A.
AU - Quintana-Murci, Lluís
AU - Barreiro, Luis B.
AU - Perry, George H.
N1 - Publisher Copyright:
© 2018 National Academy of Sciences. All Rights Reserved.
PY - 2018/11/27
Y1 - 2018/11/27
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85057223484&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85057223484&partnerID=8YFLogxK
U2 - 10.1073/pnas.1812135115
DO - 10.1073/pnas.1812135115
M3 - Article
C2 - 30413626
AN - SCOPUS:85057223484
SN - 0027-8424
VL - 115
SP - E11256-E11263
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 48
ER -