Several biological processes alter DNA sequences, leading to new gene variants. These processes include mutations (changes in the DNA sequence), gene flow (the transfer of genetic material between populations), sexual reproduction (which shuffles existing genetic variations through recombination), and horizontal gene transfer (the movement of genetic material between organisms other than by the transmission of DNA from parent to offspring). For example, a single base substitution in a gene can create a new allele, which may encode a protein with altered function or no function at all.
The generation of new gene variants is fundamental to evolution. It provides the raw material upon which natural selection acts, allowing populations to adapt to changing environments. Without this variation, populations would be less able to respond to environmental pressures, increasing their risk of extinction. The understanding of these processes has revolutionized fields such as medicine, agriculture, and conservation biology, providing insights into disease resistance, crop improvement, and biodiversity management.