Native American Japan debunked Jomon

Popular theory of Native American origins coming from Japan debunked

Popular theory of Native American origins debunked by genetics and skeletal biology

Latest scientific findings suggest the ancestral Native American population does not originate in Japan, as believed by many archeologists

Native American Japan debunked Jomon
Popular theory of Native American origins coming from Japan, debunked by genetics and skeletal biology. Jomon teeth vs Native American teeth. Photo credits: G. Richard Scott, University of Nevada Reno

A widely accepted theory of Native American origins coming from Japan has been attacked in a new scientific study, which shows that the genetics and skeletal biology “simply does not match-up”.

The findings, published today in the peer-reviewed journal PaleoAmerica, are likely to have a major impact on how we understand Indigenous Americans’ arrival to the Western Hemisphere.

Based on similarities in stone artifacts, many archaeologists currently believe that Indigenous Americans, or ‘First Peoples’, migrated to the Americas from Japan about 15,000 years ago.

It is thought they moved along the northern rim of the Pacific Ocean, which included the Bering Land Bridge, until they reached the northwest coast of North America.

From there the First Peoples fanned out across the interior parts of the continent and farther south, reaching the southern tip of South America within less than two thousand years.

The theory is based, in part, on similarities in stone tools made by the ‘Jomon’ people (an early inhabitant of Japan, 15,000 years ago), and those found in some of the earliest known archaeological sites inhabited by ancient First Peoples.

But this new study, out today in PaleoAmerica – the flagship journal of the Center for the Study of the First Americans at Texas A&M University – suggests otherwise.

Carried out by one of the world’s foremost experts in the study of human teeth and a team of Ice-Age human genetics experts, the paper analysed the biology and genetic coding of teeth samples from multiple continents and looked directly at the Jomon people.

“We found that the human biology simply doesn’t match up with the archaeological theory,” states lead author Professor Richard Scott, a recognized expert in the study of human teeth, who led a team of multidisciplinary researchers.

“We do not dispute the idea that ancient Native Americans arrived via the Northwest Pacific coast—only the theory that they originated with the Jomon people in Japan.

“These people (the Jomon) who lived in Japan 15,000 years ago are an unlikely source for Indigenous Americans. Neither the skeletal biology or the genetics indicate a connection between Japan and the America. The most likely source of the Native American population appears to be Siberia.”

In a career spanning almost half a century, Scott – a professor of anthropology at the University of Nevada-Reno – has traveled across the globe, collecting an enormous body of information on human teeth worldwide, both ancient and modern.  He is the author of numerous scientific papers and several books on the subject.

This latest paper applied multivariate statistical techniques to a large sample of teeth from the Americas, Asia, and the Pacific, showing that quantitative comparison of the teeth reveals little relationship between the Jomon people and Native Americans. In fact, only 7% of the teeth samples were linked to the non-Arctic Native Americans (recognized as the First Peoples).

And, the genetics show the same pattern as the teeth—little relationship between the Jomon people and Native Americans.

“This is particularly clear in the distribution of maternal and paternal lineages, which do not overlap between the early Jomon and American populations,” states co-author Professor Dennis O’Rourke, who was joined by fellow human geneticists – and expert of the genetics of Indigenous Americans – at the University of Kansas, Jennifer Raff.

“Plus, recent studies of ancient DNA from Asia reveal that the two peoples split from a common ancestor at a much earlier time,” adds Professor O’Rourke.

Together with their colleague and co-author Justin Tackney, O’Rourke and Raff reported the first analysis of ancient DNA from Ice-Age human remains in Alaska in 2016.

Other co-authors include specialists in Ice-Age archaeology and ecology.

Shortly before publication of the paper, two other new studies on related topics were released.

A new genetics paper on the modern Japanese population concluded that it represents three separate migrations into Japan, rather than two, as previously believed. It offered more support to the authors’ conclusions, however, about the lack of a biological relationship between the Jomon people and Indigenous Americans.

And, in late September, archaeologists reported in another paper the startling discovery of ancient footprints in New Mexico dating to 23,000 years ago, described as “definitive evidence” of people in North America before the Last Glacial Maximum—before expanding glaciers probably cut off access from the Bering Land Bridge to the Western Hemisphere. It remains unclear who made the footprints and how they are related to living Native Americans, but the new paper provides no evidence that the latter are derived from Japan.

Professor Scott concludes that “the Incipient Jomon population represents one of the least likely sources for Native American peoples of any of the non-African populations.”

Limitations of the study include that available samples of both teeth and ancient DNA for the Jomon population are less than 10,000 years old, i.e., do not antedate the early Holocene (when the First Peoples are understood to arrive in America).

“We assume,” the authors explain however, “that they are valid proxies for the Incipient Jomon population or the people who made stemmed points in Japan 16,000–15,000 years ago.”

 

Peopling the Americas: Not “Out of Japan”, PaleoAmerica
(13-Oct-2021), DOI: 10.1080/20555563.2021.1940440

 

Press release from Taylor & Francis Group on the popular theory of Native American origins coming from Japan, debunked by genetics and skeletal biology.


molar size hominins

New study of molar size regulation in hominins

New study of molar size regulation in hominins

The Dental Anthropology Group at the CENIEH has tested the inhibitory cascade model to see whether it explains the size relationships and differences in shape between the different kinds of teeth, in the molar sample from the individuals identified at the Sima de los Huesos site in the Sierra de Atapuerca.
Mandíbula AT-1 de la Sima de los Huesos. Credits: Mario Modesto

The molar size relationship is one of the peculiar characteristics of the different species of hominins and various theories have been proposed to account for this, as well as the differences in shape between the different kinds of teeth (incisors, canines, premolars and molars). The latest theory, called the inhibitory cascade model, arose out of experiments with mice embryos, and in 2016 it was applied theoretically to fossil hominins, with satisfactory results.

It appeared that all hominins satisfy the inhibitory cascade model. In a paper by the Dental Anthropology Group at the Centro Nacional de Investigación sobre la evolución Humana (CENIEH), published recently in the Journal of Anatomy, this model was tested on the molar sample from the individuals identified at the Sima de los Huesos site, situated in the Sierra de Atapuerca (Burgos).

The results match the model generated in mice extraordinarily well, thus confirming the theory's utility once more. “Nevertheless, our conclusions have brought out an anomaly in the model, when it is applied to the oldest species of the genus Homo”, explains José María Bermúdez de Castro, Paleobiology Program Coordinator at the CENIEH and lead author of this work.

Increasing and decreasing patterns

In the genera Ardipithecus, Australopithecus and Paranthropus, as well as in Homo habilis, the size pattern is increasing and fits the premises of the inhibitory cascade model perfectly. The same thing happens in Homo sapiens, except that the pattern is decreasing, with the first molar larger than the second, which in turn is bigger than the third one (wisdom tooth).

Application of the inhibitory cascade model had led to the assumption that the switch from increasing to decreasing pattern would have arisen a little under two million years ago, perhaps coinciding with the transition between the genera Australopithecus and Homo. “However, in our work we noticed that this change could have required at least a million years to take place”, states Bermúdez de Castro.

The hominins from the Sima de los Huesos, which are around 430,000 years old, are a good example of that transition, whereas most specimens of Homo ergaster, Homo erectus, Homo antecessor and Homo heidelbergensis, as well as other species, do not fit the inhibitory cascade model. “Our idea is to continue our research to determine which genetic mechanisms lie behind this anomaly in the model”, says Bermúdez de Castro.

Full bibliographic information

Bermúdez de Castro et al. 2020. Testing the inhibitory cascade model in the Middle Pleistocene Sima de los Huesos (Sierra de Atapuerca, Spain) hominin sample. Journal of Anatomy. DOI: 10.1111/joa.13292
Press release from CENIEH.

Neanderthals and modern humans diverged at least 800,000 years ago

Neanderthals and modern humans diverged at least 800,000 years ago

Neanderthals and modern humans diverged at least 800,000 years ago, substantially earlier than indicated by most DNA-based estimates, according to new research by a UCL academic.

Neanderthals diverged teeth
Dental morphology. Credit: Aida Gómez-Robles

The research, published in Science Advances, analysed dental evolutionary rates across different hominin species, focusing on early Neanderthals. It shows that the teeth of hominins from Sima de los Huesos, Spain - ancestors of the Neanderthals - diverged from the modern human lineage earlier than previously assumed.

Sima de los Huesos is a cave site in Atapuerca Mountains, Spain, where archaeologists have recovered fossils of almost 30 people. Previous studies date the site to around 430,000 years ago (Middle Pleistocene), making it one of the oldest and largest collections of human remains discovered to date.

Dr Aida Gomez-Robles (UCL Anthropology), said: "Any divergence time between Neanderthals and modern humans younger than 800,000 years ago would have entailed an unexpectedly fast dental evolution in the early Neanderthals from Sima de los Huesos."

"There are different factors that could potentially explain these results, including strong selection to change the teeth of these hominins or their isolation from other Neanderthals found in mainland Europe. However, the simplest explanation is that the divergence between Neanderthals and modern humans was older than 800,000 years. This would make the evolutionary rates of the early Neanderthals from Sima de los Huesos roughly comparable to those found in other species."

Modern humans share a common ancestor with Neanderthals, the extinct species that were our closest prehistoric relatives. However, the details on when and how they diverged are a matter of intense debate within the anthropological community.

Ancient DNA analyses have generally indicated that both lineages diverged around 300,000 to 500,000 years ago, which has strongly influenced the interpretation of the hominin fossil record.

This divergence time, however, is not compatible with the anatomical and genetic Neanderthal similarities observed in the hominins from Sima de los Huesos. The Sima fossils are considered likely Neanderthal ancestors based on both anatomical features and DNA analysis.

Dr Gomez-Robles said: "Sima de los Huesos hominins are characterised by very small posterior teeth (premolars and molars) that show multiple similarities with classic Neanderthals. It is likely that the small and Neanderthal-looking teeth of these hominins evolved from the larger and more primitive teeth present in the last common ancestor of Neanderthals and modern humans."

Dental shape has evolved at very similar rates across all hominin species, including those with very expanded and very reduced teeth. This new study examined the time at which Neanderthals and modern humans should have diverged to make the evolutionary rate of the early Neanderthals from Sima de los Huesos similar to those observed in other hominins.

The research used quantitative data to measure the evolution of dental shape across hominin species assuming different divergent times between Neanderthals and modern humans, and accounting for the uncertainty about the evolutionary relationships between different hominin species.

"The Sima people's teeth are very different from those that we would expect to find in their last common ancestral species with modern humans, suggesting that they evolved separately over a long period of time to develop such stark differences."

The study has significant implications for the identification of Homo sapiens last common ancestral species with Neanderthals, as it allows ruling out all the groups postdating 800,000 year ago.

Neanderthals diverged teeth
Hominin teeth. Credit: Aida Gómez-Robles

Press release from University College London