The term heterosis, also known as hybrid vigor or outbreeding enhancement, describes the increased strength of different characteristics in hybrids; the possibility to obtain a genetically superior individual by combining the virtues of its parents.
Heterosis is the opposite of inbreeding depression, which occurs with increasing homozygosity. The term often causes controversy, particularly in terms of the selective breeding of domestic animals, because it is sometimes believed that all crossbred plants or animals are genetically superior to their parents; this is true only in certain circumstances: when a hybrid is seen to be superior to its parents, this is known as hybrid vigor. When the opposite happens, and a hybrid inherits traits from their parents that makes them unfit for survival, the result is referred to as outbreeding depression. Typical examples of this are crosses between wild and hatchery fish that have incompatible adaptations.
New word learned from THE GLOBAL BELL CURVE