Which breeding system relies on mating closely related animals?

The breeding system that relies on mating closely related animals is known as inbreeding. This practice involves pairing individuals that share a common ancestor, which can result in several genetic outcomes, including the potential for increased uniformity in certain traits, as well as the possibility of amplifying deleterious recessive traits. Inbreeding is often used in livestock production to fix desirable traits within a breed.

In contrast, outcrossing involves mating unrelated animals to introduce genetic diversity and reduce the risk of genetic defects. Random breeding does not focus on genetic relationships at all, often leading to a mixed genetic pool without any targeted traits. Crossbreeding, on the other hand, typically involves the mating of first-generation offspring from different breeds to combine desirable traits from both. These practices serve different purposes and have varying implications for the health and genetics of the resulting offspring compared to inbreeding.