The tropics are a paradise for everyone but a skeleton. Humidity keeps rainforests green, but does little to protect bodies, leading to shortages of ancient skeletal remains in Neotropical regions such as Central America.
But deep in the jungles of Belize, beneath the dry bunkers of two rock shelters, the skeletons of people who died some 9,600 years ago are exceptionally well preserved. Its bones offer a rare glimpse into the region’s largely unknown ancient genetic history.
A group of scientists has provided a new perspective on the genetic history of people in the Maya region by extracting the DNA of these ancient people. The newspaper was published in the newspaper on Tuesday. Nature Communication. Researchers have identified a previously unknown mass migration from the south more than 5,600 years ago, before intensive corn farming emerged in the area. Most closely related to speakers of today’s Chibchan languages, the migration of these people contributed to more than 50 percent of the ancestry of today’s Maya-speaking peoples.
The new results “have the potential to review and rewrite the early history of the early Americans,” said Lisa Lucero, an anthropologist at the University of Illinois at Urbana-Champaign who specializes in the ancestral Maya and was not involved in the research.
Xavier Roca-Rada, a doctoral student at the University of Adelaide, said the results “fill the gap between the earliest previously studied individuals in the Maya region and the time before Mesoamerica’s settlement.”
The new paper emerged from ongoing excavations led by authors Keith Prufer, an environmental archaeologist at the University of New Mexico, and Douglas Kennett, an archaeologist at the University of California, Santa Barbara. Researchers are excavating two rock shelters in Bladen Nature Reserve, a remote and protected area of Belize that has kept burial grounds intact for thousands of years. Dr. “People kept turning to them over and over and burying the dead,” Prufer said.
Dr. The shelters were also occupied by tool-making and cooking creatures, as evidenced by the bones of buried armadillos, deer, and one type of rodent, Prufer said. “At the bottom of the dug pit was a giant sloth fragment dating back to even before the human occupation of the sanctuary,” he said.
Excavations have also revealed a hidden, formerly slimy, layer of protection underground. About 5,000 to 6,000 years ago, before the classical period of the Maya, people gathered small Pachychilus snails for food. Dr. “They would boil them and cut off the end of the bark and eat the flesh,” Prufer said. The inhabitants of these sanctuaries feasted on these snails, and their discarded shells protected the corpses buried below. “This layer of snails actually protected the lower tombs from the Maya digging them up,” he said.
Kennet and Dr. Prufer examines these early graves to understand how the region transitioned from hunting and gathering to intensive farming of maize, chili peppers and cassava (also called cassava). Inside 2020 paperThey described evidence of maize consumption in the bones of individuals who lived between 4,000 and 4,700 years ago.
David Reich, a geneticist at Harvard Medical School, pioneered the extraction of ancient DNA from 20 people buried in shelters over 6,000 years. The analysis revealed several human migrations to the Maya region in what is now southeastern Mexico and northern Central America.
They found three distinct groups: one that lived between 7,300 and 9,600 years ago, the other between 3,700 and 5,600 years ago, and a third group of modern Mayan peoples. The first group appears to be genetically linked to a southward migration across the Americas during the Pleistocene. The second group, however, was genetically related to the ancestors of Chibchan speakers living further south.
The authors hypothesize that this population turnover came from a mass exodus from the south. “It was the amazing result,” said Dr. Kennett.
Dr. The finding reverses an old assumption that agricultural technology spread to America through the spread of crops and practices—the spread of knowledge as opposed to the spread of humans, Reich said. The authors write that the new results show that this migration was critical for spreading farming, such as in a scenario where Chibchan speakers migrated north with maize varieties and then planted and spread them in local populations.
Dr. “People were actually moving south into the region carrying these domesticated plants as well as their knowledge systems of how to grow them,” Kennett said.
David Mora-Marín, a linguistic anthropologist at the University of North Carolina at Chapel Hill and author of the paper, conducted an analysis of the early Chibchan and Mayan languages. He found that a term for maize had spread from the Chibchan language to the Maya languages, which also supported the idea that maize was of Chibchan origin.
ancient DNA domain criticized because of the lack of ethical or proper relationship with the communities that may have descended from the ancient peoples under study.
Dr. Kennet and Dr. Prufer conducted their archaeological research with the Ya’axché Conservation Trust, a Belizean nonprofit made up largely of descendants of Maya communities. The researchers consulted with these communities, presented the results of the studies, and translated summaries of the findings into Mopan and Q’eqchi’ at the request of the local population. In discussions, communities expressed a desire to learn more about the diets of cave-dwelling ancient people and their pre-colonial family units. Dr. Kennett said that because of these conversations, the authors put more emphasis on these issues in the article.
Krystal Tsosie, a genetics researcher at Vanderbilt University, said she would like to see a more detailed explanation of how community feedback impacted the paper. Dr. “The appropriate engagement process also means properly and transparently giving community members credit for informing and enriching research,” Tsosie said.
Ripan Malhi, a genetic anthropologist at the University of Illinois at Urbana-Champaign, noted that the authors uploaded ancient DNA data to a public database. Ancient DNA could offer a shortcut to the DNA of modern populations without their consent. “This could have implications for the present-day Mayas in the region,” he said.
Dr. Lucero and Mr Roca-Rada said more data is needed to substantiate the researchers’ hypothesis that a southern migration brought maize to the Maya region. Dr. According to Lucero, the real question is whether researchers should obtain this data. “Should we dig up the ancestors?” He asked. “Do we want someone to dig into ours to answer interesting but not vital research questions?”
Kennet and Dr. Prufer last visited Belize in January 2020 to present the preliminary results of the new paper to the Mayan communities. The pandemic has since banned the return of researchers, but Dr. Prufer said they hope to return this summer to continue digging, and “will keep our promise to come back as we work every year and will update everyone.”