Which process involves gene flow occurring due to the actual migration of populations?

The process of gene flow due to the actual migration of populations is referred to as gene migration. This term is used to describe the movement of genetic material between distinct populations, which can occur when individuals from one population move and interbreed with individuals from another population. This interbreeding introduces new alleles into the gene pool, thus enhancing genetic diversity and potentially altering the evolutionary trajectory of the populations involved.

Gene migration can have significant implications for the populations, as it enables the sharing of adaptive traits and helps to maintain genetic variation. This contrasts with other terms in the choices provided, which do not accurately capture the concept of gene flow associated with migration. For instance, "hominoid transfer" is not a commonly recognized term in genetics, and "genetic shift" generally refers to shifts in allele frequencies within a population rather than migration-induced gene flow. "Genotypic transfer" also lacks specificity regarding the migration aspect and does not typically denote the movement of individuals. Therefore, gene migration is the most precise term for the process by which populations exchange genetic material through actual migration.