BIOLOGY 1M03 Lecture Notes - Lecture 6: Frequency-Dependent Selection, Heterozygote Advantage, Genetic Drift
17 Jan 2015
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Document Summary
Genetic drift (stronger in small populations, decreases diversity) Non-random mating: biased gene ow between human populations. Non-random mating: inbreeding impact of inbreeding on genotype frequencies. Genetic drift is of great concern to conservation biologists because the small populations found on nature reserves or in zoos are especially susceptible to it. Genetic drift can be caused by any event or process that involved sampling of alleles from one generation to another. Example: javan rhino and loss of genetic diversity due to drift. Originally widespread in se asia within 3 subspecies. Vietnamese javan rhino had 12 individuals in 2006, but the last survivor was shot by a poacher in 2010. Now only population is in ujung kulon national park; probably ~40 individuals. Lose genetic variation each cycle and this species is losing variation faster than mutation can be introduced. A genetically homogeneous population could be exploited by nature selection. Founder e ects can be cause by factors other than physical isolation.
