A variant (from Latin: varius “different”) is an alternative form of a gene. Most genes have multiple variants, which may occur naturally or as the result of human intervention, such as through mutation or genetic engineering. Variants arise when a new mutation occurs in a population of organisms. The distribution and frequency of variants within a population are important parameters that affect the evolution of that species.
The term variant can also refer to differences between individuals within a species, such as between members of different races or subspecies (such as between humans and Neanderthals). These individual variations are caused by different alleles of the same genes. Finally, the term variant can refer to changes in DNA sequence that may have functional consequences for the organism (such as mutations that lead to disease).