Question

rn

It is said, that the harmful alleles get eliminated from population over a period of time, yet sickle cell anaemia is persisting in human population. Why?

rn

Answer 1

When the alleles are lethal or result in decreased survival rate of individual (death before sexual maturity) then the alleles are not transmitted from one generation to other. Hence, they get eliminated from the population. Sickle cell anemia is caused due to point mutation in the allele. The individuals which are heterozygous for this allele can survive and hence sickle cell anemia persists in population.