AMY1A (amylase, alpha 1A)

Alpha amylase 1 (AMY1) is a salivary endo-enzyme responsible for hydrolysis of α-1,4 glycosidic linkages in starch to produce maltose, maltriose, and other oligosaccharides. It is the most abundant protein in human saliva but is also highly variable. This variability has been linked to changes in copy number variation with individuals with higher copy number trending to have higher protein levels. AMY1 shows high copy number variability with measured numbers anywhere from 2-15 copies and individuals from populations that consume a high starch diet tend to have higher copy number than those who do not. High starch consumption societies may have been subject to positive selection for higher copy numbers as higher AMY1 levels aid in more complete digestion of starchy foods. Chimps, Bonobos, and Orangutans show no evidence of amplified AMY1 copy number which likely is the result of their low starch diets. It has been hypothesized that individuals with more copies of AMY1 may be protected against death from Diarrheal disease and intestinal disease, as well as show dietary preference for high starch foods.