the correlation between starch consumption and number of amy1 copies suggests that more amy1 copies in high starch populations is caused by natural selection. it is a favorable phenotype for those individuals. therefore, it is likely that having more copies of amy1 in a high starch population increases fitness and produces healthier, fitter offspring. geographically close populations with different eating habits possess a different number of copies of the amy1 gene. this offers strong evidence that natural selection has acted on this gene.