Question

A dominant disease causes illness starting in middle age, reducing reproductive success by 10% on average. A new treatment is developed that prevents any effects of the disease in heterozygotes; however, homozygotes for the deleterious allele still suffer the 10% reduction in reproductive success. Assume that the deleterious allele was at equilibrium before the treatment, and that the treatment is made available to everyone who needs it. After a long time, how will the frequency of the allele have changed?

a) It will increase.

b) It will fix.

c) None of the other answers are correct.

d)It will stay the same.

e) It will decrease.

Answer 1

Ans. B

After a long time due to genetic drift which refers to change in allelic frequency due to random chance. Over the long run genetic drift favour either the elimination Or the fixation of an allele that is when it's frequency reaches 0 % Or 100 % in population respectively.