In humans, the amy1 gene produces the enzyme amylase in cells of the salivary glands. amylase breaks down starch (a polysaccharide) into the sugar maltose (a disaccharide). people from cultures with diets high in starch produce more amylase than people from cultures with diets low in starch because of a mutation in the amy1 gene. explain in two to three sentences why the frequency of this amy1 mutation would have increased in frequency in populations with a high starch diet.