Wild & genetics
Coefficient of inbreeding (COI)
The probability that an animal inherited two identical copies of a gene from a shared ancestor — a single number for how closely related its parents were.
It is calculated from a pedigree, and it depends entirely on how many generations you count: a figure over five generations and a figure over ten are different numbers for the same dog, so the depth has to be stated for the value to mean anything.
What it predicts is recessive disease and lost vigour. Two copies of the same faulty gene are how a recessive condition shows up, and a rising coefficient across a closed studbook means more of the population carries the same problems. Breeders use it to choose pairings that widen the pool rather than narrow it.
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More in Wild & genetics
HybridisationBreeding between two distinct populations or species — the main threat to wildcats, because a wildcat that breeds with a domestic cat leaves offspring that are neither.IntrogressionGenes moving from one population into another and staying there, carried in by hybrids that go on to breed back with the parent population.TNRHumanely trapping free-roaming cats, neutering and ear-tipping them, and returning them to where they were found instead of removing or killing them.FeralA domestic animal living wild — descended from domesticated stock, unsocialised to people, and genetically still a domestic animal rather than a wild species.LandraceA local population shaped over generations by climate, terrain and the job it does, rather than by a written standard and a closed studbook.DomesticationThe long genetic change that turns a wild population into one adapted to living alongside people — distinct from taming, which happens to an individual.