What is the primary driver of genetic variance within populations?

• A. Gene flow
• B. Natural selection
• C. Mutation
• D. All of the above

Answer: (D)

Genetic variance within populations is significantly influenced by several processes, and the presence of multiple factors highlights the complexity of evolution and genetic diversity. All the options provided—gene flow, natural selection, and mutation—contribute to genetic variance in distinct and complementary ways.

Gene flow, the movement of genes between populations through migration or interbreeding, introduces new alleles into a population. This introduction can increase genetic diversity and alter allele frequencies, which contributes to variance.

Natural selection, on the other hand, sorts existing genetic variants based on their fitness, leading some alleles to become more common over generations while others diminish. This differential survival and reproduction can shape the genetic composition of a population, further contributing to its variance.

Mutation is the original source of new genetic variation. Mutations create new alleles, some of which may provide beneficial traits that are acted upon by natural selection. Without mutations, there would be no new genetic diversity for evolution to act on.

Since each of these processes plays a vital role in shaping genetic variance, acknowledging all of them together provides a comprehensive understanding of how genetic diversity is maintained and evolves within populations.