A classic example of bottleneck effect is:
Bottleneck effect arises when population size crashes dramatically due to catastrophe, disease or overhunting, as in northern elephant seals reduced to about twenty individuals, leaving survivors with limited variation. Subsequent expansion retains reduced diversity and increased homozygosity, elevating inbreeding depression. Unlike founder effect involving new colony, bottleneck involves local reduction. Conservation concerns focus on maintaining variation despite crash. Hence it represents Northern elephant seal reducing genetic diversity. This concept integrates genetics, ecology and molecu
Ref: Hartl & Clark, Principles of Population Genetics, Chapter 7: Drift.
