Affected individuals show jerky, uncontrolled movements of head and limbs, progressive mental deterioration. Y small, carries few genes. Another new wrinkle Genetic Disorders range from modest nuisances to lethal Carriers Frequency of heterozygotes in population. Still not great, but riskier. Average life-span with CF is 30 years.
Water is prevented from passing from bloodstream into lung passages.
Still binds oxygen at normal conc., but at low oxygen conc. Therefore has selective advantage. Tay-Sachs 1 in 30 Jews of Russian origin is carrier. BUT if detected early, can control diet, prevent symptoms. No danger after age 9.