What does outcrossing mean?
Outcrossing is a technical term for the mating of organisms from different populations, breeds, or genetic lines. It is especially common in animal breeding, plant genetics, and conservation programs, where it may be used to introduce genetic variation into a population. The adjective outcrossing describes breeding practices, animals, or programmes involving this process, while outcross can serve as a verb. In biological usage, outcrossing is commonly contrasted with inbreeding: mating within the same population or line tends to increase homozygosity, whereas crossing between distinct lines can preserve or introduce genetic diversity. The word should not be read merely as “going outside”; it belongs mainly to specialist vocabulary, although its basic sense is straightforward. As a present participle, outcrossing can also describe the act of breeding across lines, as in a phrase such as outcrossing cattle with animals from another herd.
The mating or crossing of organisms from genetically distinct populations, breeds, varieties, or breeding lines.
"Regular outcrossing helped maintain genetic diversity in the flock."
The plural outcrossings is grammatically regular but less common than the uncountable use.
Relating to or involving breeding between organisms from different populations, breeds, varieties, or lines.
"The farm maintains an outcrossing programme for its cattle."
This use often describes a breeding system, practice, animal, or programme.
To mate or breed organisms from different populations, breeds, varieties, or lines.
"Farmers outcross local cattle with animals from another herd."
Usually used in animal breeding, horticulture, or genetics.
The plural is grammatically regular but uncommon; outcrossing is often used without a plural form.
"The pedigree records showed that the outcrossings had been carefully planned."
Outcrossing can widen a gene pool by bringing alleles from different populations into the same family tree.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does outcrossing come from?
The word is English and is formed from out- plus crossing, with crossing derived from cross. In this compound, out- conveys movement beyond the boundaries of a population, breed, or line, while crossing refers to mating or combining. The cross element traces through English to Old English cros, which came from Latin crux.
Related word forms
How outcrossing is actually used
This is primarily technical vocabulary in genetics, breeding, horticulture, and conservation. It may describe either naturally occurring mating or breeding deliberately managed by humans, and it is more general than crossbreeding.
Easily confused with outcrossing
Crossbreeding specifically combines established breeds, whereas outcrossing more broadly refers to breeding between genetically distinct populations or lines and may occur without deliberate human management.