Adaptações humanas a dieta, subsistência, e ecorregião são devidas a mudanças sutis na frequência de alelos

quarta-feira, julho 21, 2010

Human adaptations to diet, subsistence, and ecoregion are due to subtle shifts in allele frequency
  1. Angela M. Hancocka
  2. David B. Witonskya,
  3. Edvard Ehlera,b,
  4. Gorka Alkorta-Aranburua
  5. Cynthia Beallc,
  6. Amha Gebremedhind,
  7. Rem Sukernike
  8. Gerd Utermannf
  9. Jonathan Pritcharda,g,
  10. Graham Coopa,h, and 
  11. Anna Di Rienzoa,1
-Author Affiliations

  1. aDepartment of Human Genetics, University of Chicago, Chicago, IL 60637;

  2. bDepartment of Anthropology and Human Genetics and Department of Biology and Environmental Studies, Charles University, Prague, 128 00 Czech Republic;

  3. cDepartment of Anthropology, Case Western Research University, Cleveland, OH 44106;

  4. dDepartment of Internal Medicine, Addis Ababa University, Addis Ababa, Ethiopia;

  5. eLaboratory of Human Molecular Genetics, Department of Molecular and Cellular Biology, Institute of Chemical Biology and Fundamental Medicine, Russian Academy of Sciences, Novosibirsk, 630090 Russia;

  6. fInstitute for Medical Biology and Human Genetics, Medical University of Innsbruck, 6020 Innsbruck, Austria;

  7. gHoward Hughes Medical Institute, University of Chicago, Chicago, IL 60637; and

  8. hSection for Evolution and Ecology and Center for Population Biology, University of California, Davis, CA 95616


Human populations use a variety of subsistence strategies to exploit an exceptionally broad range of ecoregions and dietary components. These aspects of human environments have changed dramatically during human evolution, giving rise to new selective pressures. To understand the genetic basis of human adaptations, we combine population genetics data with ecological information to detect variants that increased in frequency in response to new selective pressures. Our approach detects SNPs that show concordant differences in allele frequencies across populations with respect to specific aspects of the environment. Genic and especially nonsynonymous SNPs are overrepresented among those most strongly correlated with environmental variables. This provides genome-wide evidence for selection due to changes in ecoregion, diet, and subsistence. We find particularly strong signals associated with polar ecoregions, with foraging, and with a diet rich in roots and tubers. Interestingly, several of the strongest signals overlap with those implicated in energy metabolism phenotypes from genome-wide association studies, including SNPs influencing glucose levels and susceptibility to type 2 diabetes. Furthermore, several pathways, including those of starch and sucrose metabolism, are enriched for strong signals of adaptations to a diet rich in roots and tubers, whereas signals associated with polar ecoregions are overrepresented in genes associated with energy metabolism pathways.



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