any of a number of areas on the Earth from which arose important crop plants and domestic animals. As few as four of these centres of origin have probably provided the great majority of the most useful plants and animals: (1) tropical southeastern Asia—rice, chickens; (2) temperate southwestern Asia—wheat, sheep, goats, asses; (3) subtropical or temperate Mexico and Central America—corn (maize), turkeys; and (4) the central Andes of South America—potatoes, guinea pigs, llamas. Genecentres were located in mountainous regions in temperate and tropical climates that historically were areas of fairly high population.