Diet and the evolution of human amylase gene copy number variation
Diet and the evolution of human amylase gene copy number variation
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DOI：
10.1038/ng2123
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发表时间：
2007-10-01
期刊：
影响因子：
30.8
通讯作者：
Stone, Anne C.
中科院分区：
文献类型：
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作者：
Perry, George H.;Dominy, Nathaniel J.;Stone, Anne C.
淀粉消耗是干旱环境下农业社会和狩猎采集者的一个显著特征。相比之下，雨林和环北极地区的狩猎采集者和一些牧民消耗的淀粉要少得多（1-3）。这种行为差异提出了不同的选择压力作用于淀粉酶（负责淀粉水解的酶）的可能性(4)。我们发现，唾液淀粉酶基因（AMY1）的拷贝数与唾液淀粉酶蛋白水平呈正相关，并且高淀粉饮食人群的个体平均比传统低淀粉饮食人群的AMY1拷贝数更多。与这些人群子集中的其他基因座的比较表明，AMY1拷贝数分化的程度非常不寻常。据我们所知，这个拷贝数可变基因正选择的例子是在人类基因组中首次发现的例子之一。较高的AMY1拷贝数和蛋白质水平可能会改善淀粉类食物的消化，并可能缓冲肠道疾病降低健康的影响。
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 starch(1-3). This behavioral variation raises the possibility that different selective pressures have acted on amylase, the enzyme responsible for starch hydrolysis(4). 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.