THE INVENTION OF MAIZE.

THE INVENTION OF MAIZE. When I was reading about archaeology as a boy, it seemed that most of the information about prehistory was unknowable. Carbon dating had been discovered and was a huge breakthrough, but DNA has provided knowledge that seemed lost forever. This article by Sean B. Carroll describes how researchers now know a great deal about how maize was developed—not only the plant it was derived from, but also where it was developed and when. The ancestor of maize is a Mexican grass called teosinte. The article has a wonderful picture of modern corn (maize) and teosinte side by side. There is a stark contrast between what we know as corn on the cob and teosinte, with 12 kernels “wrapped inside a stone-hard casing.” The location where maize was first grown has now been pinned down to the Central Balsas River Valley in southern Mexico because that is where the teosinte most similar to maize is found. The time of the domestication of maize has been dated to 9000 years ago based on the genetic distance between ancient teosinte and modern maize. This date is confirmed by the find of tools with maize residue in the Central Balsas River Valley in deposits which were 8700 years old. It is thought that the domestication process took from several hundred to several thousand years. In light of yesterday’s post, I note that I see no indication that trade was involved in the domestication of maize.