The movement of genes into and out of a gene pool is called gene migration. Genetic variation is enhanced by the process of gene migration.
Gene migration provides several advantages to populations. It gives a population the variability necessary to adapt to changing conditions, protecting the survival of the species. Gene migration allows beneficial, neutral and harmful mutations to transfer between populations. The beneficial mutations provide a means for each species to adapt in a way that ensures survival of the fittest. Selection will choose the better-adapted individuals. Gene migration also encourages similarity between populations. Similarities prevent divergence of species.