What is the Difference Between Assortative and Disassortative Mating?

Assortative and disassortative mating are two phenomena that result in the mating of organisms in a species. The key difference between them lies in the similarity of the phenotypes of the mating partners:

• Assortative mating (also known as positive assortative mating or homogamy) is a mating pattern where individuals with similar phenotypes or genotypes mate with one another more frequently than would be expected under random mating conditions. This phenomenon increases genetic relatedness within a family.
• Disassortative mating (also known as negative assortative mating or heterogamy) is a mating pattern where individuals with dissimilar phenotypes mate with one another more frequently than would be expected under random mating conditions. This phenomenon reduces the mean genetic similarities within the population and increases genetic variation.

In general, assortative mating occurs more frequently than disassortative mating due to homotypic preferences, which increase relatedness between mates and between generations. Disassortative mating, on the other hand, is often associated with heterotypic preferences, which can increase genetic variation within a population. Both assortative and disassortative mating patterns can have different effects on the genetic structure and diversity of a population, depending on the specific traits involved and the environmental context in which the mating occurs.

Comparative Table: Assortative vs Disassortative Mating

Here is a table comparing assortative and disassortative mating:

Assortative mating occurs between phenotypically similar organisms, while disassortative mating occurs between phenotypically different organisms. Assortative mating tends to follow the Hardy-Weinberg equilibrium, whereas disassortative mating does not. Assortative mating results in offspring with increased similarity, while disassortative mating leads to offspring with increased dissimilarity.