Jan 26
Genetic Drift results from random changes in allele frequencies
●Very strong in small populations
Population bottleneck: if a population is reduced to only a small number of individuals,
genetic drift will reduce genetic variation in the population
A colonizing population is unlikely to have all the alleles present in the whole population
- This is called a founder effect (equivalent to a population bottleneck)
In large populations, genetic drift can influence frequencies of alleles that do not affect
survival and reproduction
- This is where the term “drift” comes from (allele frequencies drifting up and down
randomly)
Nonrandom mating occurs when individuals choose mates with particular phenotypes,
instead of just choosing at random
- EX: self-fertilization is common in plants
- If individuals choose the same genotype as themselves, homozygote frequencies
will increase
