Inbreeding is reproduction from the mating of parents who are closely related genetically. Inbreeding results in increased homozygosity, which can increase the chances of offspring being affected by recessive or deleterious traits. This generally leads to a decreased fitness of a population, which is called inbreeding depression. An individual who results from inbreeding is referred to as inbred. The avoidance of expression of deleterious recessive alleles caused by inbreeding is thought to be the main selective force maintaining the outcrossing aspect of sexual reproduction. (See also Inbreeding depression.)
Livestock breeders often practice controlled breeding to eliminate undesirable characteristics within a population, which is also coupled with culling of what is considered unfit offspring, especially when trying to establish a new and desirable trait in the stock.
In plant breeding, inbred lines are used as stocks for the creation of hybrid lines to make use of the effects of heterosis. Inbreeding in plants also occurs naturally in the form of self-pollination.
Famous quotes containing the word inbreeding:
“Be reflective ... and stay away from the theater as much as you can. Stay out of the theatrical world, out of its petty interests, its inbreeding tendencies, its stifling atmosphere, its corroding influence. Once become theatricalized, and you are lost, my friend; you are lost.”
—Minnie Maddern Fiske (18651932)