GUARANTEED SUCCESS
Overdominance heterozygotes have higher fitness than either homozygotes because of
equilibrium of allleles
underdominance heterozygotes have lower fitness than either homozygotes because one
allele is fixated while the other is lost
frequency dependent selection fitness dependent upon frequency of phenotype or
genotype in population, in rarer cases selection can also maintain frequency of alleles in
population
Mutation ultimate source or raw material of genetic variation
Mutation-Selection balance frequencies of alleles at equilibrium, rate at which deleterous
allele being alienated is equal to rate at which new copies are being created by mutation
mutation selection balance with small selection coefficient mutation rate high, allele freq
high = mildy deleterous
mutation selection balance with large selection coefficient mutation rate low, allele freq low
= highly deleterous
, Non random mating does not cause allele frequencies to change but can affect course of
evolution
Migration movement of alleles between populations, homogenize allele frequency across
populations
gene flow transfer of alleles from gene pool of one population to another population
Fst value group of populations + reflects variation in allele freq. among populations in the
group (scale of 0-1)
Large Fst values indicates more variation in allele freq. among populations
Low Fst values populations homogenized by gene flow (similair allele frequencies)
migration in participating population migration impacts allele freq change from one
generation to the next
migration in small populations migration is a potent mechanism of evolution, usually
migrants are from larger populations, chance events have outcomes that differ from the
theoretical