The Blue People of Kentucky

Troublesome Creek in Eastern Kentucky Isolated hill country Local people married relatives Passed rare, recessive disease to offspring

Methemoglobinemia Recessive allele for gene on chromosome 22 Diaphorase enzyme deficiency Reduces oxygen carrying capacity of red blood cells Causes cyanosis (bluish color of skin), shortness of breath, and heart disease

Fugate Descendants

Fugate Pedigree Complete Fugate Pedigree Analysis using these genotype symbols: BB = unaffected individuals Bb = carriers bb = affected individuals

Pedigree of the Blue People of Troublesome Creek, Kentucky Square = male Circle = female Horizontal connecting line = parents Double connecting line = marriage between close blood relatives Vertical line = offspring Filled in = affected individual Half filled = carrier (heterozygous)