Exploring the relationship between lifestyles, diets and genetic adaptations in humans

Abstract

BackgroundOne of the most important dietary shifts underwent by human populations began to occur in the Neolithic, during which new modes of subsistence emerged and new nutrients were introduced in diets. This change might have worked as a selective pressure over the metabolic pathways involved in the breakdown of substances extracted from food. Here we applied a candidate gene approach to investigate whether in populations with different modes of subsistence, diet-related genetic adaptations could be identified in the genes AGXT, PLRP2, MTRR, NAT2 and CYP3A5.ResultsAt CYP3A5, strong signatures of positive selection were detected, though not connected to any dietary variable, but instead to an environmental factor associated with the Tropic of Cancer. Suggestive signals of adaptions that could indeed be connected with differences in dietary habits of populations were only found for PLRP2 and NAT2. Contrarily, the demographic history of human populations seemed enough to explain patterns of diversity at AGXT and MTRR, once both conformed the evolutionary expectations under selective neutrality.ConclusionsAccumulated evidence indicates that CYP3A5 has been under adaptive evolution during the history of human populations. PLRP2 and NAT2 also appear to have been modelled by some selective constrains, although clear support for that did not resist to a genome wide perspective. It is still necessary to clarify which were the biological mechanisms and the environmental factors involved as well as their interactions, to understand the nature and strength of the selective pressures that contributed to shape current patterns of genetic diversity at those loci.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-015-0212-1) contains supplementary material, which is available to authorized users.

Evidence for a Common Origin of Blacksmiths and Cultivators in the Ethiopian Ari within the Last 4500 Years: Lessons for Clustering-Based Inference

“…This suggests the Ari groups are more similar to each other, in terms of how their ancestry relates to the non-Pagani donors, than any other groups sampled within Ethiopia used in this study. Furthermore in analysis (B), in contrast to what you might expect under the RN hypothesis as originally formulated [ 5 ], the ARIc are not more closely related to groups currently classified as farmers [ 27 ] than the ARIb ( Fig 3 , S8 Fig , S11 , S15 and S16 Tables).…”

“…Under a hypothetical RN setting, we again note that in order to have any power to distinguish the ARIc and ARIb genetically, our analyses must include at least one sampled group whose ancestors split more recently from those of the ARIc than those of the ARIb and ARIc split from each other. Our dataset contains several Ethiopian groups (Afar, Amhara, Anuak, Tigray, Wolayta) assigned as agriculturalists in [ 27 ], whose ancestors plausibly could have split more recently from those of the Cultivators than those of the Blacksmiths and Cultivators split from each other, under a hypothetical RN setting. Also, two groups (ORO,MKK) have F ST values with ARIc that are lower than those between ARIb and ARIc ( Fig 1b , S3 Table ), suggesting either or both could represent such a sampled group(s).…”

“…In contrast, harmonizing the RN model with the data analysed here requires an additional assumption beyond this bottleneck effect, namely (1) that we have not sampled a group whose ancestors split more recently from either Ari group than the Ari groups’ ancestors split from each other, or (2) that there were substantial levels of intermixing between the ancestors of ARIb and ARIc since the two groups initially were isolated from one another. Assumption (1) is perhaps less likely given our analyses included other Ethiopian groups described as agriculturalists [ 27 ] and groups that are more genetically similar to the ARIc than the ARIc are to the ARIb using the measures noted above. Assumption (2) is plausible under a RN model, given the two groups currently reside together.…”

Arylamine N-Acetyltransferases in Anthropology

“…Specifically, because of the established link between many NAT2 alleles and NAT2 acetylation capacity, the distribution of NAT2 phenotypes prevalence in different parts of the world could be inferred ( Fig. 1) and was shown to vary substantially between populations (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)48). In particular, a significant difference in slow acetylation prevalence between agriculturalists and hunter-gatherers was found both in sub-Saharan Africa and globally at the worldwide scale, with the notable exception of the American continent.…”

Variation in NAT2 acetylation phenotypes is associated with differences in food-producing subsistence modes and ecoregions in Africa

“…These hypotheses have been fuelled by the finding of significantly different frequency distributions of acetylation phenotypes between agriculturalists and hunter-gatherers, both in sub-Saharan Africa [ 44 ] and globally at the worldwide scale [ 25 , 38 , 45 ]. In addition, significant differential acetylation prevalence between sedentary agriculturalists and nomadic pastoralists has been reported in Central Asia [ 43 ].…”