As I've been posting about effective population and inbreeding, I thought this re-post would be appropriate.
Begin repost
Reading a bit about inbreeding and population bottlenecks I came upon the extreme example of the northern elephant seal. In the late 19th century its population was reduced to about 20 individuals (undiscovered and isolated on a Mexican island). Today, there are around ~100,000 northern elephant seals. Compared to the southern elephant seal the northern hemisphere species exhibits far less genetic variation (surprise!). A relatively recent paper concluded that the diversity of southern elephant seals on a particular MHC locus was comparable to humans. While the northern elephant seal can be characterized by two mtDNA haplotypes (frequencies of 0.275 and 0.725) the southern elephant seal on South Georgia Island alone exhibits 23 mtDNA haplotypes (Hedrick 2000).
This sort of data makes it intuitively clear why population
long term effective population of a ...
