In population genetics, gene flow is best defined as which of the following processes affecting allelic frequency changes?

• A. A random change in allele frequencies due to sampling error, strongest in small populations
• B. The movement of alleles between populations through migration of individuals or their gametes, altering allele frequencies
• C. A consistent increase in the frequency of the most fit allele due to differential survival and reproduction
• D. A change in allele frequencies caused by new mutations arising in a population over time

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of gene flow in population genetics. Gene flow refers to the transfer of alleles or genes from one population to another, which can change allele frequencies in the receiving population.
2. Step 2: Recognize that gene flow occurs through the movement of individuals or their gametes (such as pollen or sperm) between populations, allowing alleles to be introduced or removed.
3. Step 3: Differentiate gene flow from other evolutionary processes: genetic drift (random changes in allele frequencies), natural selection (differential survival and reproduction), and mutation (new alleles arising).
4. Step 4: Identify that gene flow specifically involves migration and the resulting exchange of genetic material, which can increase genetic similarity between populations or introduce new alleles.
5. Step 5: Conclude that the best definition of gene flow is the movement of alleles between populations through migration of individuals or their gametes, altering allele frequencies.