Bio115-lecture36

• 1. Calculate the allelic frequencies
• 2. Find the expected genotypic frequencies
• 3. Compare the observed and expected genotypic frequencies using a chi-square test

In general, the degrees of freedom for a chi-square test of Hardy-Weinberg equilibrium equal the number of expected genotypic classes minus the number of associated alleles

Tendency for individuals sharing a particular trait to mate

Tendency for individuals that do not share a particular trait to mate

Preferential mating between related individuals

Avoidance of mating between related individuals

Inbreeding leads to an increase in homozygosity at all loci, but no change in allele frequencies

The increased appearance of lethal and deleterious traits with inbreeding

• Mutation
• Migration
• Genetic Drift
• Natural selection

Sampling error/random effects due to small population size

• Gene pools of populations become more similar
• Increases genetic variation within the recipient population

the divergence of populations and often results in one allele becoming fixed

• Founder Effect
• Genetic bottleneck

• 1. Change in allelic frequency
• 2. Reduced genetic variation
• 3. Different populations diverge genetically with time

The differential reproduction of genotypes when individuals with adaptive traits produce a greater number of offspring than that produced by others in the population

The reproductive success of one genotype compared with the reproductive successes of other genotypes in the population

Divide the mean number of offspring produced by a genotype by the mean number produced by the most prolific genotype

The relative intensity of selection against a genotype

s = 1 - W

know table 25.4

• Selection against a dominant allele is very efficient
• Selection against an autosomal recessive allele is inefficient
• Balancing selection where the heterozygous genotype is most fit

calculate relative fitness and next generation frequency of an allele

Equilibrium reached between forward and reverse mutations

Equilibrium reached when allelic frequencies of source and recipient population are equal

Fixation of one allele

• Directional selection: fixation of one allele
• Overdominant selection: equilibrium reached