Which process describes alleles entering a population by immigration and leaving by emigration, thereby countering genetic drift?

Which process describes alleles entering a population by immigration and leaving by emigration, thereby countering genetic drift?

• A. Gene Flow
• B. Genetic Drift
• C. Mutation
• D. Natural Selection

Answer: (A)

Gene flow is the movement of alleles between populations through immigration and emigration. When individuals move in or out, they bring or remove genetic variants, which tends to make populations more similar and can counteract the random changes of genetic drift, especially in small populations where drift can quickly fix or lose alleles. In other words, gene flow can maintain or introduce variation by mixing alleles across populations, offsetting the random fluctuations drift would cause. Genetic drift is the random change in allele frequencies due to sampling effects, not driven by movement between populations. Mutation introduces new alleles within a population but doesn’t involve alleles moving from one population to another. Natural selection changes allele frequencies based on differential survival and reproduction, not on migration of individuals.

Gene flow is the movement of alleles between populations through immigration and emigration. When individuals move in or out, they bring or remove genetic variants, which tends to make populations more similar and can counteract the random changes of genetic drift, especially in small populations where drift can quickly fix or lose alleles. In other words, gene flow can maintain or introduce variation by mixing alleles across populations, offsetting the random fluctuations drift would cause.

Genetic drift is the random change in allele frequencies due to sampling effects, not driven by movement between populations. Mutation introduces new alleles within a population but doesn’t involve alleles moving from one population to another. Natural selection changes allele frequencies based on differential survival and reproduction, not on migration of individuals.