BIOB51H3 Lecture Notes - Lecture 13: Muscle Atrophy, Allele Frequency, Neurodegeneration
Document Summary
In equilibrium, not slow decline: why isn"t it lost, hypothesis 1: negative frequency-dependent selection, no, there is no fluctuation in allele frequency or fitness, hypothesis 2: heterozygote superiority, no evidence of higher fitness for heterozygote in any cases. Heterozygote superiority: sickle cell malaria advantage, net effect: persists in areas where it may not make sense, maladaptive, migration maintains variation, migration-selection balance, so, the net event of selection depends on the environment. Migration: migration = gene flow, add individuals that provide new alleles, gene pool is different that it would have been with original population. Interbreeding is necessary when moving from one population to another: occurs in, plants, animals, humans, effect of migration, small population large population, little effect on large population, large population small population, big effect on small population. Genetic drift: change in allele frequency from chance variation in the lifetime reproductive success of individuals.
