Drift, Gene Flow, Mutation and Non-Random Mating

Question 1

effective population size (Ne)

Answer 1

number of individuals that would lose genetic variability at the same rate as the population with N individuals, only fraction of individuals

Question 2

extinction vortex

Answer 2

consequence of genetic drift and inbreeding, small population, leads to pop that “circles the drain” and becomes extinct

Question 3

founder effect

Answer 3

genetic drift, new pop founded by few individuals, caused by dispersion (no death event)

Question 4

genetic bottleneck

Answer 4

genetic drift, number of individuals in a pop drastically reduced, loss of genetic diversity/entire alleles (ex: northern elephant seal/california sea otter)

Question 5

gene flow

Answer 5

violates H-W principle of isolation, introduces alleles from other pops, slow down/prevent local adaptions

Question 6

genetic drift

Answer 6

violates H-W condition of large pop, may lead to fixed alleles/mutational meltdown

Question 7

inbreeding

Answer 7

result of small pops due to genetic drift (founder effect/bottleneck), can lead to deleterious alleles becoming fixed

Question 8

mutation

Answer 8

violates the H-W condition of no mutations, produces new alleles/genes/chromosomes, most mutations are neutral or bad but some are advantageous, can lead to extinction/natural selection

Question 9

mutational meltdown

Answer 9

too many deleterious alleles become fixed and population declines/becomes extinct

Question 10

positive/negative assortative mating

Answer 10

violated H-W condition of random mating, non random mating can change genotype freqs

positive: like mates w like, reduces heterozygosity (ex: human height)
negative: like less likely to mate w like, increases heterozygosity, aka dissassortative (ex: red heads, MHC diff s)