The Hardy-Weinberg law and selective mating.

The genotype equilibrium of the Hardy-Weinberg law is not maintained if mating in a population is selective. Two trends can be distinguished.

• If individuals prefer mating partners of their own genotype this will decrease the occurrence - and eventually lead to the elimination - of heterozygotes: MM individuals will always produce MM offspring, NN individuals will always produce NN offspring. MN individuals mating with MN individuals will produce offspring of genotypes MM, NN and MN. This increases the number of homozygotes and decreases the relative proportion of heterozygotes. Eventually heterozygotes will disappear from the population.
• If individuals prefer partners of a different genotype this will lead to an icnrease in heterozygotes. But no matter how many heterozygotes there are in a population, some offspring will still be either MM or NN, so the homozygotes will never disappear completely.

home