How can migration influence genetic diversity?

Migration can significantly influence genetic diversity within a population by introducing new alleles. When individuals from one population move to another and interbreed with the resident population, they can bring alleles that were not previously present in the gene pool. This influx of genetic material increases the overall genetic variation, which is crucial for the adaptive potential of the population. Increased genetic diversity can enhance a population's ability to adapt to changing environments, resist diseases, and overall improve the resilience of the population.

In contrast, while the other choices hint at various genetic phenomena, they do not accurately capture how migration positively contributes to genetic diversity. For instance, decreasing allele frequencies pertains more to the effects of genetic drift or selective pressures rather than migration’s role in adding genetic variation. Homogenization is a potential outcome of migration but does not directly reflect the introduction of new alleles. Lastly, while migration can affect local adaptation, it does not inherently eliminate these adaptations; rather, it can also introduce complexity into adaptive scenarios by mixing different beneficial traits from diverse genetic backgrounds.