Diet and the Evolution of Human Amylase gene copy number variation

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The PDF is an interesting read since some of us like to eat

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http://www.biologia.uniba.it/dottorato/J_Club/1390-amylase.pdf

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

H 1,2, iel J Dominy3, Katrina G Claw1,4, Arthur S

Lee2, Heike Fiegler5, Redon5, Werner4, A

Villanea3, Joanna L Mountain6, Rajeev Misra4, Nigel P 5,

Lee2,7,8 & Anne C Stone1,8

Top of pageStarch 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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School of Human Evolution and Social Change, Arizona State

University, Tempe, Arizona 85287, USA.

Department of Pathology, Brigham and Women's Hospital, Boston,

Massachusetts 02115, USA.

Department of Anthropology, University of California, Santa Cruz,

California 95064, USA.

School of Life Sciences, Arizona State University, Tempe, Arizona

85287, USA.

The Wellcome Trust Sanger Institute, The Wellcome Trust Genome

Campus, Hinxton, Cambridge CB10 1SA, UK.

Department of Anthropological Sciences, Stanford University,

Stanford, California 94305, USA.

Harvard Medical School, Boston, Massachusetts 02115, USA.

These authors contributed equally to this work.

Correspondence to: iel J Dominy3 e-mail: njdominy@...