Biology 1001A Lecture Notes - Lecture 15: Founder Effect, Genetic Drift, Natural Selection
3 Apr 2016
School
Department
Course
Professor
Document Summary
Selection and fitness outcomes, difference between relative vs absolute fitness and how to calculate each. Absolute fitness (w): average number of surviving offspring for a particular genotype: lifetime reproductive success, factors affecting: attract mate, fertile to produce gametes, provide care to offspring. Relative fitness (w): standardize absolute fitness to get this: do this by defining fittest genotype (leaves most surviving offsprings in a population) and make its relative fitness =1, other genotypes in population, w is between 0-1. Strength of selection refers to magnitude of difference between genotypes in terms of relative fitness: how the dominance status of alleles affects the response to selection. Strength of selection influences speed/rate at which evolution occurs (end up at same endpoint though) Even if an allele is dominant, if it is selected against, the allele can still disappear. Dominant alleles cannot hide from the effects of selection. Recessive allele hides and is sheltered: effect of heterozygote advantage and heterozygote disadvantage on genetic variation.
