Outbreeding is a term used to describe the union of genetically unrelated individuals within the same species. Outbreeding promotes genetic variability and vitality within a breeding population by eliminating homozygous individuals. Harmful recessive alleles have a better chance of being repressed by the dominant alleles in heterozygous individuals, thus reducing the number of negative mutations.

Outbreeding promotes the genetic diversity and, hence, the overall fitness of a species. By producing new and varied combinations, outbreeding is a starting point of natural selection and the foundation of evolution. Outbreeding is an important tool in the continued survival of a species.