BIOB 375 1st Edition Lecture 36 Outline of Last Lecture I. Population GeneticsOutline of Current Lecture II. Population Genetics IICurrent LectureHow do populations change over timeDoes reproduction change genotypic and allelic frequencies?The Hardy-Weinberg law:If – A population is large, randomly mating and not affected by mutation, migration or natural selection,Then –- The allelic frequencies of a population do not change- The genotypic frequencies stabilize after one generation Hardy-Weinberg Equilibrium Does reproduction change genotypic and allelic frequencies?- Reproduction alone will not change the genetic structure of a population.What would?- Mutation - Migration- Natural selection- Genetic drift: changes in allele frequencies due to chance factorsThe effect of mutation on allelic frequencies over time:- Mutation changes allelic frequencies- Allelic frequencies reach equilibrium eventually- Change in allelic frequencies due to mutation in one generation is very smallThe effect of migration ( gene flow) on allelic frequencies over time:- Increase the genetic variation within the recipient population - Cause the gene pools to become more similarThe effect of natural selection on allelic frequencies over time:- Depends on the fitness values of the genotypes in the populationo Fitness is defined as the relative reproductive success of a genotypeSelection coefficient(s) = the relative intensity of selection against a genotype- The bigger s, the higher selection against that
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