Amish Populations in Lancaster County,Pennsylvania Have High Rates of a Rare

Essay

Amish populations in Lancaster County,Pennsylvania have high rates of a rare form of dwarfism.The recessive allele that codes for this disorder is found in 1 of 14 individuals in this Amish population,in contrast to 1 in 1,000 in the general population.In Ohio,an Amish population suffers with higher than normal rates of cystic fibrosis and a host of other genetic diseases so rare that some have not yet been named.What factors have caused such severe genetic problems in these two communities?