Answer to Question #109757 in Evolution for rebekajo

Question

If the original population of 200 (from question #1) was hit by a tsunami and 100 organisms were wiped out, leaving 63 homozygous recessive out of the 100 survivors. Assuming that all individuals were equally likely to be wiped out, how did the tsunami affect the predicted frequencies of the alleles in the population? (Hint: Assume the new population is at equilibrium – AFTER the event – so you are comparing two populations which are at equilibrium to look for changes in allele frequencies.)

Answer 1

In this case the homozygous recessive have higher fitness (a scenario known as homozygous recessive advantage or overdominance), the tsunami will maintain multiple alleles at stable equilibrium frequencies. An equilibrium can also persist in a population if the fitness associated with a genotype decreases as that genotype increases in frequency.