Question

Under what conditions is it most likely that genetic drift will lead to fixation of deleterious alleles

Answer 1

Genetic drift is a mechanism in which allelic frequencies are changed by chance or we can say by sampling error. Fluctuation in allelic frequency (harmful or useful) by random event is observed in genetic drift. Genetic drift possibly works in finite small population. In large population genetic drift is decreases due to natural selection. If the selection is weak, in the small population than genetic drift overcome the effect of natural selection. So genetic drift leads to fixation of deleterious alleles in smaller population with weak selection. It can reduced population viability and this population has higher risk of extinction. In larger population the rate of natural selection is very high. Alleles which are most suitable for current habitat will be fixed so deleterious alleles are vanished over generations. In large population with strong genetic selection, frequency of deleterious alleles decreases generation after generation.