How does migration affect genetic variation between populations?

Migration, often referred to as gene flow, involves individuals moving between populations, which affects the genetic makeup of those populations. When individuals migrate from one population to another, they bring their unique alleles with them. This movement can introduce new genetic material into the receiving population, which can lead to an increase in genetic variation within that population.

However, when populations are small or genetically distinct, the migration of a few individuals can also homogenize the genetic differences between populations over time. This is particularly relevant when it comes to populations that have been isolated from one another for extended periods. In such cases, the introduction of genes from a migrant population can reduce the genetic differentiation between populations, effectively decreasing the genetic variation they have when compared to each other.

Therefore, while migration promotes genetic diversity within a population, it typically reduces genetic variation between different populations, which is essential to understand when studying population genetics and evolutionary processes. The understanding of these dynamics is crucial, as they demonstrate the interplay between migration, genetic variation, and the overall adaptation and resilience of species.