The fugate family, also known as the "blue people of kentucky" have a condition known as methemoglobinemia which prevents hemoglobin from carrying oxygen and makes it difficult for unaffected hemoglobin to release oxygen to body tissues. these individuals had a blue complexion, but were otherwise healthy, with many living into their 80's or 90's. these individuals generally have methemoglobin levels of 10-20% of total hemoglobin. how does genetic drift account for the consistency of this level of methemoglobin?