In the case of underdominance, it turns out that the positive equilibrium frequency of alleles A and a given by,
is unattainable. This means that unless the initial allele frequencies are these exact equilibrium frequencies,the positive equilibrium frequencies will never be reached. For this reason, we call such a equilibrium unstable.
The stable equilibria are the monomorphic states, (peq, qeq) = (1, 0), in other words all individuals have genotype AA, and, (peq, qeq) = (0, 1), i.e. all individuals have genotype aa. These monomorphic equilibria are said to be locally stable because what happens to the allele frequencies as t → ∞ depends on the initial allele frequencies (p0 and q0). In particular, if (p, q) → (peq, qeq) = (0, 1) as t → ∞.
Using this information, what happens to the frequency of allele A as t → ∞ if q0 = 0.9 and the fitness values for genotypes AA: Aa : aa are 1.8: 1 : 1.2, respectively?
|
|