When a small number of individuals moved to the United States from Germany, they established an Amish population. Why do you often see a higher prevalence of some rare diseases in these new founder populations? When a small number of individuals moved to the United States from Germany, they established an Amish population. Why do you often see a higher prevalence of some rare diseases in these new founder populations? Higher mutation rate in the new population. Alleles that are rare in the ancestral population (Germany) become common in the new population by random chance. Natural selection favors disease causing mutations in the new population. Negative assortative mating in the new population.

Alleles that are rare in the ancestral population (Germany) become common in the new population by random chance.

Explanation:

The founder effect is the change in the allele frequencies of a population by a chance event when a small group of individuals migrate from the large original population and colonize a new region. The gene pool of the Amish population is quite different from the original population as the colonizing individuals did not carry all the alleles and genes present in the original population.

The founder effect results in the expression of harmful recessive alleles that were otherwise masked in the heterozygous genotype of the original large population. Small colonizing population exhibits increased homozygosity and reduced genetic variations leading to the expression of rare diseases that were masked by heterozygosity in the large parent population.