Genetic viability is the ability of the genes present to allow a cell, organism or population to survive and reproduce.[1][2] The term is generally used to mean the chance or ability of a population to avoid the problems of inbreeding.[1] Less commonly genetic viability can also be used in respect to a single cell or on an individual level.[1]
Inbreeding depletes heterozygosity of the genome, meaning there is a greater chance of identical alleles at a locus.[1] When these alleles are non-beneficial, homozygosity could cause problems for genetic viability.[1] These problems could include effects on the individual fitness (higher mortality, slower growth, more frequent developmental defects, reduced mating ability, lower fecundity, greater susceptibility to disease, lowered ability to withstand stress, reduced intra- and inter-specific competitive ability) or effects on the entire population fitness (depressed population growth rate, reduced regrowth ability, reduced ability to adapt to environmental change).[3] See Inbreeding depression. When a population of plants or animals loses their genetic viability, their chance of going extinct increases.[4]