The primary source of genetic diversity in a population comes from mutations. Mutations are changes in the DNA sequence that can introduce new alleles into a gene pool. These alterations can occur due to various factors, such as environmental influences, errors during DNA replication, or genetic recombination during reproduction. While many mutations are neutral or harmful, some can be advantageous, providing a survival benefit that influences natural selection. This genetic variability is essential for evolution and adaptation of species to changing environments.