GN 301 Lecture Notes - Lecture 18: Restriction Fragment Length Polymorphism, Mitochondrion, Genetic Drift
Document Summary
Malaria is prevented in people who have hbs allele because parasite cannot live there. Salmonella attached to functioning proteins to enter cell: protein channels do not work and bacteria cannot attach, lactose intolerance and culture. Low lactase levels lead to gas, cramps, nausea after eating lactose food. If (cid:448)ariation isn"t herita(cid:271)le, it is not passed do(cid:449)n. Selection is genetic and environmental: causes of population freq change. Leads to genetic drift: random fluctuation in allele freq. Leads to founder effect: ex: tristan da cuhna, clinodactyly, bent pinky. Increase homogeneity: manly recessive traits which are usually the diseased ones. Selection: unequal reproduction by diff genotypes, directional selection. Favor one extreme: population mean increase or decreases depending on which extreme is favored. Stabilizing selection: heterozygous favored, decreased variance, polymorphism, both alleles present in population, disruptive selection, advantage for both extremes. Less heterozygotes but high both homozygote types: evidence. Lower levels have simpler life; upper is more complex: geographic distribution.
