deliberate inbreeding

Inbreeding is the mating of closely related individuals. This practice is used to retain desirable traits or eliminate undesirable ones. However, it often leads to offspring with reduced vigor, size, and fertility due to the combination of recessive harmful genes from both parents.1

Mild inbreeding has been used in some dog breeds and extensively in laboratory mice and rats to ensure consistent responses in research. Despite its uses, inbreeding in domestic animals generally results in decreased fertility, slower growth, increased susceptibility to disease, and higher mortality rates. To counteract these negative effects, crossbreeding is often employed to introduce more diverse genes. The opposite of inbreeding is outbreeding, which involves mating unrelated individuals.213