| Type | Fitness relation | Form of selection | Result |
|---|---|---|---|
| 1 | W11 = W12 > W22 | Directional selection against recessive allele A2 | A1 increases, A2 decreases |
| 2 | W11 = W12 < W22 | Directional selection against dominant allele A1 | A2 increases, A1 decreases |
| 3 | W11 > W12 > W22 | Directional selection against incompletely dominant allele A2 | A1 increases, A2 decreases |
| 4 | W11 < W12 < W22 | Directional selection against incompletely dominant allele A1 | A2 increases, A1 decreases |
| 5 | W11 < W12 > W22 | Overdominance | Stable equilibrium, both alleles maintained |
| 6 | W11 > W12 < W22 | Underdominance | Unstable equilibrium |
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Note: W11, W12, and W22 represent the fitnesses of genotypes A1A1, A1A2, and A2A2, respectively. |
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