Inbred

Inbred describes an individual or lineage derived from mating between closely related individuals. In genetics, inbreeding increases homozygosity of alleles across the genome, raising the chance that recessive deleterious alleles are expressed.

Causes include small population size, mating within a limited pedigree, cultural or religious practices, or deliberate selection in breeding programs. Even occasional mating between relatives can raise inbreeding levels over generations.

Consequences: Inbreeding can lead to inbreeding depression, reduced fertility, higher neonatal mortality, susceptibility to disease, lower lifespan, and expression of genetic disorders. The magnitude depends on the population's genetic diversity and the degree of relatedness.

In humans, consanguineous marriages, such as between first cousins, are a cultural practice in some regions and are associated with an increased risk of autosomal recessive disorders. In animals, many purebred lines exhibit substantial inbreeding, which can fix desirable traits but also increase health problems. In plants, inbreeding can be used to produce uniform inbred lines for hybrids; however, self-pollination can reduce vigor if not managed.

Management and mitigation: In conservation and agriculture, strategies include outcrossing, rotating breeding pairs to increase diversity, genetic rescue, maintaining effective population size, and careful monitoring of inbreeding coefficients. Ethical considerations arise in human contexts, with laws and guidelines varying by country.