Kevin William Wann

Plant domestication, or the evolution of wild plants to suit human usage, facilitated the development of farming and civilizations. While most research has focused on the domestication of grain crops, tree fruit evolution played an additional important role in early diets. The avocado (Persea americana Mill.) is an economically valuable tree fruit domesticated in the American tropics; however, scholars understand very little regarding when, where, and how it fell under domestication. The DNA of an ancient Mayan avocado, excavated from Honduras, was compared to a panel of modern wild and domesticated relatives. Results show that the ancient sample was much closely related to a modern domesticated variety than to wild Honduras trees, suggesting that by this time the domestication process was well underway and involved the long-range distribution of high-quality fruits, ignoring local wild genetic variation. An ethnobotanical undertaking was additionally conducted in Nicaragua and Southern Mexico, in which interviews with rural farmers and a genetic assessment of their native avocado cultivars showed that many modern domesticated varieties in Central America result from an ancient migration event from South America.