Exam 21: Population Genetics

The northern elephant seal,Mirounga angustirostris,suffered a significant population bottleneck in the late nineteenth century,when hunting reduced their population size to as few as 20 individuals.It has since rebounded to several tens of thousands.The related southern elephant seal,M.leonine,was not hunted as intensively.What prediction can you make about the relative levels of heterozygosity in populations of these two species?

Allele frequencies can change across the geographic range of a species according to climate,geological features,or direction in the range.For instance,a certain allele frequency might go up along with the elevation or down as you go south in the species' range.This systematic change in frequency is referred to as