Inbreeding

Inbreeding is a term in genetics, meaning the crossing (mating) of closely related animals or plants.^[1] Self-fertilisation in plants is the most extreme kind of inbreeding. It is quite widespread in plants which carry both male and female flowers on the same plant.^[2] Inbreeding is the opposite of outcrossing, which is the mating of unrelated members of the same species. The combination of inbreeding and outcrossing is a standard method of artificial selection.^[3]

Other terms are inbred strain, a group of organisms so inbred that they have little or no genetic variation, and inbreeding depression, which is the decreased fitness (usually lack of fertility and early illness and death) brought about by inbreeding.

Inbred strains, for example of mice or drosophila, are often used in biology as model organisms when genetic uniformity makes them useful in investigation of such things as drugs and cancer.

For human beings, inbreeding is destructive, and almost all cultures have an incest taboo. For example, many prohibit marriage between first cousins, and most prohibit it for closer family members.

1. ↑ Bernstein H, Byerly HC, Hopf FA, Michod RE. 1985. Genetic damage, mutation, and the evolution of sex. Science 229 (4719): 1277–81. Bibcode:1985Sci...229.1277B. doi:10.1126/science.3898363. PMID 3898363
2. ↑ Darwin, Charles 1876. The effects of cross and self fertilisation in the vegetable kindon. Murray, London.
3. ↑ Michod R.E. Eros and Evolution: a natural philosophy of sex. 1994. Perseus Books. ISBN 0-201-40754-X