Fragmented habitat compensates for the effect of genetic bottleneck
According to the population genetics theory, population subdivision helps organisms retain genetic diversity, crucial for adaptation in a changing environment. Habitat shape is thought to be important for generating and maintaining population subdivision, but empirical cases are needed to test this assumption. Saimaa ringed seals, land-locked in a labyrinthine lake and recovering from a drastic bottleneck, show much reduced genetic variation.