gene pool

The gene pool is all of the genes and their various alleles, that occur in all the members of a particular species or population of species at any given moment. For a species to be vigorous and survive, the gene pool must be large enough for natural variation to take place through cross-fertilization. A large population does not necessarily imply a large gene pool, however. For example, there is concern about the viability of some sizeable populations of cheetahs which, despite their numbers, have insufficient variation in the gene pool.