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evens out genetic differences between populations
Gene flow or migration of gene can be described as a process of transfer of genetic variation from one population into another population. This process leads to change in the frequency of a gene variant ( that is called allele) in a particular population and it reduces the genetic differences between population.
If the process of gene glow is high, then the two population will be considered equivalent in genetic diversity.
Thus, Gene flow evens out genetic differences between populations