About three thousand year old corn cob from the Al Gigante rock shelter site in Honduras. These corn chicks were genetically analyzed by an international team of scientists. December. In the 14th issue of the journal Proceedings of the National Academy of Sciences, Logan Kistler, curator of archeology and archeology at the Smithsonian National Museum of Natural History, and an international team of collaborators have identified three approximately 2,000 complete sequential genomes. Years old bed from El Gigante Rock Shelter in Honduras. An analysis of the three genomes reveals that these thousand-year-old varieties of Central American corn were of South American descent and adds a new chapter to the complex story of a tidal history of corn rearing. Combined with recent studies on corn rearing in the region, these recent findings suggest that something important happened in corn rearing in Central America about 20,000,000 years ago, and that there may be an injection of genetic diversity from South America. Something to do with it. Credit: Thomas Harper
The three-thousand-year-old cob in Honduras shows that people brought corn varieties back to Mesoamerica, possibly increasing produc productivity and shaping the culture.
About 9,000 years ago, what is known as corn does not exist today. Among the ancient peoples of southwestern Mexico, they encountered a wild grass called Tiosinte, which was smaller than a stone head kernel than the pink finger of the ear. But by genius or stroke of necessity, these indigenous farmers saw the potential of grain, added it to their diet and put it on the path to becoming a pet crop feeding billions.
No matter how important corn, or corn, is for modern life, holes remain in the understanding of its travel through space and time. Now, a team led by Smithsonian researchers has made ancient use DNA Fill in a few of those spaces.
A new study, detailing the 5,000-year history of corn, is an excellent example of how basic research into ancient DNA can gain insights into human history, which would otherwise be inaccessible, said co-lead author Logan Kistler, of archaeologists. And archeology at the Smithsonian National Museum of Natural History.
“The evolution of wild plants over thousands of years into the domestic crop we have today is the most significant process in human daily history, and corn is one of the most important crops currently grown on the planet,” Kistler said. “A better understanding of the evolution and cultural context of the home can give us valuable information about this food and its role in shaping the culture as we know it.”
An assortment of corn chicks of different ages was found at the Al Gigante rock shelter site in Honduras. Credit: Thomas Harper
In the December 14, 2020, issue of the journal Proceedings of the National Academy of Sciences, Kistler and an international team of collaborators have reported the complete sequential genomes of nearly three thousand year old cobs from the Al Gigante Rock Shelter in Honduras. An analysis of the three genomes reveals that these thousand-year-old varieties of Central American corn were of South American descent and adds a new chapter to the complex story of a tidal history of corn rearing.
“We show that humans were carrying corn back from South America to the home center of Mexico,” Kistler said. “This could have been influenced by genetic diversity which could have increased resilience or productivity. He also emphasizes that the process of compliance and crop improvement does not just travel in a straight line. “
Humans selectively began breeding the wild ancestor of corn, Tiocinta, in Mexico about 9,000 years ago, but the partial domesticated varieties of the crop did not reach the rest of Central and South America, 1,500 and 2,000 years, respectively.
For many years, the traditional thinking among scholars was that corn was first bred whole in Mexico and then spread elsewhere. However, after it turned out that 5,000,000-year-old cubs in Mexico were only partially domesticated, scholars began to consider whether the whole story of corn rearing had been captured.
Then, in a landmark 2018 study led by Kistler, scientists used ancient DNA to show that the process was still complete when people first began transporting it to Central and South America when the first steps toward the observance of Teosinta came to Mexico. Could not be done. In these three regions, the process of compliance and crop improvement has proceeded in parallel but at different speeds.
An assortment of corn chicks of different ages was found at the Al Gigante rock shelter site in Honduras. After scientists first discovered the remains of a 4,300-year-old complete corn and highly productive variety of corn in the Al Gigante Rock Shelter, a team discovered the archaeological layers around the site, producing other cubes, kernels or any other genetic material. Thing. . They also began making 4,300-year-old corn samples from the site – the oldest crop traces at Al Gigante, respectively. Over two years, the team tried to sequence 30 samples, but only three were of the right quality to sequence the entire genome. These three practical specimens came from the most recent stage of the rock shelter business – dating to the Carbon date of 2,300 to 1,900 years ago – revealing a genetic overlap between the Honduran rock shelter and the three samples of South American corn varieties. December. In the 14th issue of the journal Proceedings of the National Academy of Sciences, Logan Kistler, curator of archeology and archeology at the Smithsonian National Museum of Natural History, and an international team of collaborators reported about 3,000 complete genealogies. Years old bed from El Gigante Rock Shelter in Honduras. Analysis of the three genomes reveals that these thousand-year-old varieties of Central American corn were of South American descent and adds a new chapter to a tidal complex story of the history of corn rearing. Credit: Thomas Harper
In a previous attempt to get the details of this richer and more complex housing story, a team of scientists, including Kistler, found that the remains of a 300-year-old corn from the Central American Al Gigante Rock Shelter, a fully domesticated and highly productive variety
Mexico, Kestler and project co-lead Douglas Kennett, University of California, anthropologist gist, in Santa Barbara, has been surprised to find a fully domesticated corn in a genetically linked, area at El Gigante. Determine where al gigante corn originated.
“The El Gigante Rock Shelter is significant because the well-preserved plant in it has spread over the last 11,000 years.” “More than 10,000 cornflakes, from whole cubs to pieces and leaves, have been identified. Many of these come late in time, but an extensive study of radiocarbon has identified some of the fossils we found as early as 4,300 years ago. “
They explored the archaeological layers around the Al Gigante rock shelter for stone, kernels or anything else that could produce genetic material, and the team began working to sort out some of the site’s 4,300-year-old corn specimens – the oldest traces of the crop.
Over two years, the team tried to sequence 30 samples, but only three were of the right quality to sequence the entire genome. These three practical specimens came from the most recent level of the rock shelter business – a carbon date of 2,300 and 1,900 years ago.
With three sequential genomes of al gigante corn, the researchers analyzed them in front of a panel of 121 published genomes of different corn varieties, derived from 12 ancient corn chicks and seeds. This comparison revealed snippets of the genetic overlap between the three specimens of the Honduran rock shelter and the corn varieties of South America.
“The genetic link with South America was subtle but consistent,” Kistler said. “We repeated the analysis several times using different methods and sample compositions but kept getting the same result.”
Kissler, Kenneth and his co-authors at Texas A&M University, Pennsylvania State University, as well as the Francis Creek Institute and its affiliates. University of Warwick In the United Kingdom, assume that reproduction of these South American breeds in South America may have led to an increase in the development of more productive hybrids in the region.
Although the results only include samples of al jigante corn from about 2,000,000 years ago, Kistler said the shape and structure of the cubs from a layer about 2,000,000 years old indicate that they were almost as productive as he and his co-workers. There were writers. Able to rank. To Kistler, this means that blockbuster crop improvement could likely occur during 2,000 years or so before separating these archaeological layers at El Gigante. The team further speculates that it was the introduction of South American corn varieties and their genes, probably at least, 300 years ago, that increased the productivity of corn in the region and the prevalence of corn in the diet of the people living there. In a wider region, as has been discovered in a recent study led by Kennett.
“We’re starting to show a confluence of data from multiple Central American studies showing that corn is becoming the most productive staple crop in dietary importance 700 to 1,000,000 years ago,” Kennett said.
These latest findings, in conjunction with a recent study by Kennett, suggest that something important happened to corn rearing in Central America about 10,000,000 years ago, and that it may have some effect on the injection of South American genetic diversity. This proposed time also coincides with the appearance of the first settled agricultural communities in Mesoamerica that eventually gave birth to great cultures in the Americas, Olmec, Maya, Teotihuacan, and Aztecs, although Kistler was quick to demonstrate the idea, still considering the issue. Guess.
“We can’t wait to find out exactly what happened around the 4,000-year-old mark,” Kistler said. “There are many archaeological specimens of maize that have not been genetically analyzed. If we begin to test these specimens further, we will be able to begin answering these delayed questions about how important this reincarnation of South American species was. “
Reference: “Archaeological Central American corn genomes indicate ancient gene flow from South America” Logan Kistler, Heather B. Thackeray, Amber M. Vanderwalker, Alejandra Domic, Anders Bergstrom, Richard J. George, Thomas K. Harper, Robin G. By Albie, Kenneth Heath and Douglas J. Kennett, 14 December 2020, Proceedings of the National Academy of Sciences.
DOI: 10.1073 / PNAS.155560117
Funding for the research was provided by the Smithsonian, the National Science Foundation, Pennsylvania State University, and the Francis Creek Institute.
