Population Genetics MCAT Practice Question

A 45-year-old man with no significant past medical history is found to have elevated serum cholesterol levels during routine screening. Genetic analysis reveals he is heterozygous for a familial hypercholesterolemia mutation. His two siblings—one with the same mutation and one without—live in different geographic regions and have had children. Population genetic modeling is being used to predict how the mutation frequency might change across generations as families migrate between regions. In the original isolated region (Region A), the hypercholesterolemia allele frequency is 0.30. In a neighboring region (Region B) where families are now migrating, the allele frequency is only 0.10. After one generation of equal bidirectional migration between the two regions, what is the expected allele frequency of the hypercholesterolemia mutation in the newly mixed population?