31. 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? Â Â