- A Largely random, undirected changes in allele frequencies that occur independently of any migration event, a description that actually applies to genetic drift rather than to migration-driven gene flow itself
- B Movement of alleles between populations through migration; gene flow introduces new alleles into a population, increases genetic diversity, counters divergence between populations and can prevent speciation
- C Gene flow is understood to be the principal direct cause of new species formation through reproductive isolation, despite gene flow generally acting to homogenize populations and counteract divergence rather than to drive it
- D Gene flow is understood to be functionally identical to genetic drift, both describing mainly random allele change, though drift is driven by chance sampling while gene flow is driven specifically by the movement of individuals
Correct answer: B. Movement of alleles between populations through migration; gene flow introduces new alleles into a population, increases genetic diversity, counters divergence between populations and can prevent speciation
Explanation: Gene flow: transfer of alleles from one population to another via migrating individuals. Effects: (1) Introduces new alleles to receiving population; (2) Homogenizes allele frequencies between connected populations; (3) High gene flow prevents divergence and speciation; (4) Low gene flow allows divergence. In modern times, human transportation has increased gene flow among previously isolated human populations, reducing genetic differences between groups.
Concept context
Origin of life, Darwin's theory, natural selection, speciation, and evidence for evolution.