Population Genetics MCAT Practice Question
A scientist models allele frequency changes in a population with two alleles under complete heterozygote advantage. Individuals with genotype AA have fitness 0.9, Aa individuals have fitness 1.0, and aa individuals have fitness 0.8. If initial allele frequencies are p = q = 0.5, what outcome is predicted?
Answer choices
- AThe alleles will reach a stable equilibrium at intermediate frequenciesCorrect answer
- BThe A allele will go to fixation while a is lost
- CThe a allele will go to fixation while A is lost
- DRandom fluctuations will determine which allele becomes fixed
- EBoth alleles will be lost due to fitness disadvantage of homozygotes
- FThe allele frequencies will oscillate cyclically without ever reaching equilibrium
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