Question

Case B: In this population, the frequency of the dominant allele, B, is 0.5 and the frequency of the recessive allele, b, is 0.5. However, in this situation any individual who is born with the dominant trait has a 50 % chance of not surviving to reproductive age. Assuming that mating is still random, what will happen to the allele frequencies (p and q) after 5 generations? (le. Will one allele increase or decrease?) Prediction (1 mark): Reason (2 marks):

Answer 1

Answer:

1) According to Hardy Weinberg equilibrium, random mating doesn't alter the allele frequencies even after five years of generations, as long as other evolutionary forces such as genetic drift, mutation., etc are not acting. Hence the dominant and recessive allele frequencies remain the same. The population to be in equilibrium, it has to be large and isolated without any natural selection process to occur that doesn't take place in nature.

2) Random mating in equilibrium, there is more probability for heterozygotes than population with non-random mating. Hence, even with heterozygote advantage, the allele frequencies does not alter.