A report recently published in the Proceedings of the National Academy of Sciences strengthens the theory that maize moved northward from central Mexico to the Southwest by being passed from one hunter-gatherer band to the next, rather than solely by direct migration of people and their crops from Mexico. The international team of archaeologists summarizes the most recent archaeological evidence, and integrates what is currently known about early maize in the Southwest with genetic, paleoecological, and historical linguistic studies.
http://www.sciencedaily.com/releases/2009/12/091208162656.htm
