Inbreeding : its meaning, uses, and effects on farm animals

Abstract

"Various mating schemes of animals are classified under two broad categories-inbreeding and outbreeding. Classification depends on the closeness of the biological relationship between mates. Within each category, a wide variation in intensity of this relationship exists. A very fine line separates the two categories. Mating closely related animals (for example, parent and offspring, full brother and sister or half brother and sister) is inbreeding. With less closely related animals (first cousins, second cousins), people disagree about where to draw the line between inbreeding and outbreeding. Technically, inbreeding is defined as the mating of animals more closely related than the average relationship within the breed or population concerned. Matings between animals less closely related than this, then, would constitute outbreeding. These two systems of mating, with varying intensities in each, are illustrated in Figure l. Matings indicated within the inbreeding category are self-explanatory; those within the outbreeding category are defined in the glossary."--First page.