Despite the fact that maize was domesticated about nine thousand years ago to dominate the diet of the inhabitants of Central America it was only about four thousand years ago. This is the conclusion reached by scientists who analyzed isotope analysis of human remains from two caves in the mountains of Belize. The results of their study published in the journal Science Advances.
Corn (Zea mays) is one of the most popular cereals in the world. According to genetic data, this grain began to be domesticated on the territory of modern Mexico approximately nine thousand years ago, after which he complex ways spread in North and South America. However, until now, remained unknown exactly when corn occupied a dominant position in the diet of inhabitants of the region.
To answer this question is decided, a team of researchers led by Douglas Kennett (Douglas J. Kennett), University of California, Santa Barbara. The researchers analyzed the ratio of carbon isotopes in 52 human skeletons, discovered in two residential caves in the Maya mountains in Belize. In these shelters the bones and teeth of people accumulated over the last ten thousand years that made them unique to Central American source of archaeological information.
In the remains of age from 4700 to 9600 years was marked by low levels of the isotope 13C. This shows that while the small population of the Maya mountains rarely used in food plants that use With4-photosynthesis, including maize. Mostly Central Americans relied on wild plants of the rainforest and fed their animals.
It may seem strange that people for nearly four thousand years virtually ignored already domesticated culture. This paradox is explained by the fact that initially the cobs and grain of maize were too small for human consumption, and had been grown for the sweet juice from the stem used for the preparation of alcoholic beverages. Only the appearance of mutant plants and further selection turned this grass into a valuable food resource.
The first evidence of the diet with the corn content of more than 25 per cent belong to the time interval from 4700 4000 years ago. The data of isotopic analysis clearly indicated that eating grains this cereal. However, the degree of dependence on him throughout this transition period vary greatly from person to person.
4000 years ago, the corn finally took a consistently high — over 70 per cent share in the diet of the inhabitants of Central America. As evidenced by paleoecological reconstruction, from that moment began a massive land clearing for agriculture. Isotopic analysis data from other parts of Latin America show that there corn was the basis of the diet later. For example, in South America it happened 3500 years ago, and in the North — 2,500 years ago.
Previously, researchers were able to clarifyhow evolution occurred is another important agricultural crops — rice. It turned out that its diversification and distribution started about four thousand two hundred years ago. If the rice is grown mainly in China, later appearing species penetrated into Korea, Japan and Southeast Asia.
Sergey Knee High