The gene flow is a popular and individual genetic material that transfers from one population to another.
This involves different types of events such as pollen being driven to an entirely new destination or people migrating to a new place.
Migration from one popular place to another is also responsible for a change in allele frequencies which covers a proportion of members to carry a particular variant of a gene.
Example of gene flow:
Europeans inhabit North America and mate with Native Americans.
Dogs are also seen in a variety along with the globe due to interspecies mating.