Answer: There are several factors affecting genetic variation:
1. Mutation: This is a change in DNA sequence that can occur spontaneously or due to other environmental factors.
2. Recombination: This occurs during meiosis when homologous chromosomes exchange genetic material, resulting in the formation of new combinations of genes.
3. Gene flow: The movement of genes from one population to another, which can introduce new genetic variation.
4. Genetic drift: The random fluctuation of gene frequencies in a population, which can lead to the loss of genetic variation over time.
5. Natural selection: The process by which certain traits are favored or disfavored based on their ability to contribute to an organism's survival and reproductive success, which can result in changes in the frequency of particular genes.