Analysis of ancient teeth challenges theory that Native Americans originated in Japan

Analysis of the teeth revealed that Native Americans were not directly descended from the Jomon people in ancient Japan. (Image credit: Shutterstock)

Native Americans may not have originated in Japan, as previous archaeological evidence has suggested, according to a new study of ancient teeth.

For years, archaeologists had predicted that the first people to live in North America were descended directly from a group called the Jomons, which occupied ancient Japan about 15,000 years ago, around the same time people arrived. in North America about 15,000 years ago via the Bering Land Bridge. , a strip of land that previously connected Russia to North America before sea level rose above it. This theory is based on archaeological similarities in stone tools, particularly projectile weapons, found in Native American and Jomon settlements.

However, the authors of the new study claim that this scenario is highly unlikely because the biological evidence “simply does not match” with the archaeological findings, according to one. researchers’ statement.

Related: 10 things we learned about our human ancestors in 2020

“The Jomons were not directly ancestral to Native Americans,” lead author G. Richard Scott, an anthropologist at the University of Nevada, Reno, told Live Science. “They [the Jomon] are more aligned with Southeast Asian and Pacific groups than with East Asian and Native American groups. “

Instead, researchers suspect that Native Americans descended from a different group living somewhere in East Asia, although much uncertainty remains as to exactly where and when these ancestors lived.

An archaeological theory

Scott and his colleagues began their study because they weren’t convinced by the main argument linking Native Americans to the Jomon – the similarities to stone tools, they said.

“The similarities in artifacts between ancient Jomon and at least some of the earliest known Native American sites reside in rod projectile points,” said co-author John Hoffecker, archaeologist at the Arctic and Alpine Research Institute of the University of Colorado Boulder. Live Science. These similarities led previous researchers to suspect that the knowledge needed to make these tools had been passed down from culture to culture, he added.

A collection of stone arrowheads found in ancient Jomon settlements. (Image credit: Shutterstock)

Researchers in the study said that this evidence was not convincing enough to draw a conclusion. “Cultural parallels are not unusual,” Scott said. “People can borrow ideas from others or independently find similar solutions to the same problems.”

Instead, researchers turned to genetic analysis to uncover the origins of Native Americans.

“I think paleo-genetics adds a tremendous amount of information to reconstructions of population history,” Scott said. “It does not supplant archeology but has become an important complementary method that can solve problems that archaeologists cannot address.”

Teeth analysis

To examine the genetic links between the two groups, researchers turned to teeth, which can provide a wealth of genetic information.

“The dental crown and root morphology have been studied extensively in twins and families, and there is no doubt that they are under genetic control,” Scott said. Unlike other genetic traits, such as blood group, which are controlled by a single gene, tooth morphology is polygenic, which means it is influenced by a combination of many different genes, he added.

For example, in another recent study, a version of a gene, known as EDAR V370A, was recently found to change the shape of the shovel-shaped incisors by about 20% in people with the condition. that would make this gene very easy to identify and track over time using dental records, Scott said.

A comparison highlighting the difference between Jomon and Native American teeth. (Image credit: G. Richard Scott)

This means that the shape of teeth (and their roots) can provide researchers with a lot of information about a person’s genetic origins and how close two individuals are to each other. Additionally, tooth shape is rarely influenced by environmental factors, making it a reliable way to consider ancestry.

“A change in the environment does not trigger a change in tooth morphology,” Scott said. “You can invent styles of similar artefacts, but you cannot invent your tooth shape.”

In this study, Scott and his team compared 25 features of dental morphology in approximately 1,500 sets of ancient teeth from Native Americans and Jomon dating back over 10,000 years, as well as other ancient groups from Asia. East, Southeast Asia and the Pacific.

This analysis of the features of the teeth and the DNA in the teeth revealed that the Native Americans were not close enough to the Jomon people to consider them ancestors, but that they may have come from another unknown group of East Asia, Scott said.

“The authors present a compelling argument for eliminating the Japanese Jomon people as direct ancestors of the early Native Americans,” Brian Fagan, an archaeologist at the University of California at Santa Barbara who was not involved in the process, told Live Science. ‘study. “This is a major advance in our knowledge of the early Americans.”

Uncertain origin

Although the study suggests that Native Americans did not descend directly from the Jomon people as previously thought, the two groups would have shared a much older common ancestor, Scott said.

“The common ancestor of Jomon and the Amerindians could go back several millennia [more than 30,000 years], while the common ancestor of East Asians and Native Americans is more recent [less than 30,000 years ago]”said Scott.

However, it is not known exactly who the East Asian ancestors of Native Americans were. The “most likely point of origin is what many call Greater Beringia,” a region of Northeast Asia connected to the Bering Land Bridge and now in modern Siberia, Scott said. But “at the moment there are limited remains of this area, so it is difficult to be more precise,” he added.

Researchers also believe that Native Americans lived in isolation for several generations before migrating to North America – another factor that makes it more difficult to determine their exact genetic origins.

“The ancestors of the Amerindians were probably stranded in Beringia at the end of Pleistocene [when ice sheets and glaciers would have trapped them] until conditions improve enough to allow travel along the west coast of North America, ”said Scott. “And during this period of isolation, they differentiated themselves from the ancestral populations of East Asia. “

However, recent discoveries, including the discovery of footprints in New Mexico dating as far back as 23,000 years, have called into question the exact date of people’s arrival in North America, Previously reported live science.

“Unfortunately, we cannot solve this problem with the available data,” Scott said.

The study was published online on October 13 in the journal PaleoAmerica.

Originally posted on Live Science.

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