Which process is responsible for increasing genetic variation in a population?

Mutation is a fundamental process that introduces new genetic material into a population, thereby increasing genetic variation. Mutations can occur spontaneously during DNA replication or as a result of environmental factors, leading to changes in an organism's traits. When these mutations occur in reproductive cells, they can be passed on to future generations, contributing to the genetic diversity within that population.

This genetic variation is essential for evolution because it provides the raw material upon which natural selection can act. Variable traits can lead to differences in survival and reproduction, allowing certain mutations to become more prevalent over time. In this context, while natural selection, genetic drift, and gene flow are important processes that can influence genetic variation and its distribution within populations, they do not directly introduce new genetic variants as mutations do.

Natural selection acts on existing variation, favoring individuals with advantageous traits. Genetic drift can lead to random changes in allele frequencies, especially in small populations, but it can also result in the loss of genetic variation. Gene flow refers to the transfer of genes between populations, which can introduce new alleles but is contingent on existing variation being present. Thus, mutations are the primary source of new genetic variation within a population.