Gene flow occurs when individuals from one population move to another and interbreed with members of that population. The flow of genes does not lead to a change in the frequencies of the alleles. However, a change in the gene frequencies may occur in the local population. The genes of migrant individuals due to free crossing with aboriginal individuals are included in the gene pool of this population. The process increases the genetic diversity of the population. At the species level, gene flow maintains the stability of the genetic structure of the species, preventing gene drift. Gene flow creates a stock of variations that provide the ability of a population to adapt to changing habitat conditions. New variants of genes contribute to the emergence of new features that can affect the organism fitness to changes in the habitat.