What happens to the frequency of homozygotes and heterozygotes as a result of positive assortative mating?

Positive assortative mating occurs when individuals with similar phenotypes or genotypes preferentially mate with one another. This behavior tends to increase the frequency of homozygotes because when similar individuals mate, they are more likely to share the same alleles. As a result, their offspring are more likely to be homozygous for those alleles.

In contrast, heterozygotes are produced when individuals with different alleles mate, which is less likely to happen in a population practicing positive assortative mating. Therefore, the frequency of heterozygotes tends to decrease as homozygotes become more prevalent. This shift in genetic composition can lead to a reduced level of genetic diversity in the population over time.

The overall result of positive assortative mating is an increase in homozygosity among individuals in the population, confirming that the frequency of homozygotes increases as a direct consequence of this mating pattern.