Letter abstract


Nature Genetics 39, 1256 - 1260 (2007)
Published online: 9 September 2007 | doi:10.1038/ng2123

Diet and the evolution of human amylase gene copy number variation

George H Perry1,2, Nathaniel J Dominy3, Katrina G Claw1,4, Arthur S Lee2, Heike Fiegler5, Richard Redon5, John Werner4, Fernando A Villanea3, Joanna L Mountain6, Rajeev Misra4, Nigel P Carter5, Charles Lee2,7,8 & Anne C Stone1,8

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Starch consumption is a prominent characteristic of agricultural societies and hunter-gatherers in arid environments. In contrast, rainforest and circum-arctic hunter-gatherers and some pastoralists consume much less starch1, 2, 3. This behavioral variation raises the possibility that different selective pressures have acted on amylase, the enzyme responsible for starch hydrolysis4. We found that copy number of the salivary amylase gene (AMY1) is correlated positively with salivary amylase protein level and that individuals from populations with high-starch diets have, on average, more AMY1 copies than those with traditionally low-starch diets. Comparisons with other loci in a subset of these populations suggest that the extent of AMY1 copy number differentiation is highly unusual. This example of positive selection on a copy number–variable gene is, to our knowledge, one of the first discovered in the human genome. Higher AMY1 copy numbers and protein levels probably improve the digestion of starchy foods and may buffer against the fitness-reducing effects of intestinal disease.

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  1. School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona 85287, USA.
  2. Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
  3. Department of Anthropology, University of California, Santa Cruz, California 95064, USA.
  4. School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA.
  5. The Wellcome Trust Sanger Institute, The Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.
  6. Department of Anthropological Sciences, Stanford University, Stanford, California 94305, USA.
  7. Harvard Medical School, Boston, Massachusetts 02115, USA.
  8. These authors contributed equally to this work.

Correspondence to: Nathaniel J Dominy3 e-mail: njdominy@ucsc.edu

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