Prehistoric teeth found over 100 years ago are some of the best evidence yet for hybridized communities of Neanderthals and modern humans.
We know that Neanderthal and early modern humans intervened — our DNA tells us — but fossil evidence in this regard is surprisingly lacking. Hence the importance of the new research paper published today in the Journal of Human Development.
In evidence are prehistoric teeth recovered from the site of La Cotte de Saint Brede cave in Jersey in 1910 and 1911, which were erected in 1910 and 1911. The teeth, corresponding to two individuals, exhibit characteristics consistent with intertrapping. Presence of hybridized populations.
Now there is “considerable DNA evidence that interbreeding occurred from both fossils and the modern genome,” said Chris Stringer, a co-author of the new study and an archaeologist at the Museum of Natural History, London. Indeed, most people of recent ancestry outside Africa have about 2% of Neanderthal DNA in their genome. He said that archaeologists “still have not known the exact conditions, nor that there was a blending absorption in the expansion of modern human populations of Neanderthals,” Stringer said.
Communities of mixed ancestral communities, which existed during the Middle Paleolithic, some 48,000 years ago, are likely evidence that “extinction” is probably not the best term to describe the fate of Neanderthals. These homines and their DNA, instead, were absorbed by the increasingly dominant newcomers in Europe: modern humans (Homo sapiens).
La cotte de st. Brelade’s cave was occupied for over 200,000 years. Excavations conducted in the early 20th century led to the discovery of more than 20,000 stone tools, as well as the bones of mammals and woolly rhinoceros. The exceptionally low sea levels during the last ice age made it possible for groups to migrate to the Channel Islands.
The teeth, 13 of them, were found in a single spot on a ledge behind a stove. The fossils were kept as a single set and belonged to a single Neanderthal individual. Stringer, along with colleagues from the UCL Institute of Archeology, the University of Kent, and other institutions, borrowed teeth from the Jersey Museum and Art Gallery to perform analysis with modern methods and equipment, including CT scans.
One of the 13 teeth had disappeared over the years, and the other was found to be related to some type of animal. The remaining 11 teeth, it was determined, belonged to not one but two individuals. Importantly, the teeth exhibited signs of hybridization.
“We find the same unusual combination of Neanderthal and modern human traits in the teeth of both identified Neanderthal individuals,” Stringer said. “We consider this to be the strongest direct evidence found in fossils, although we do not yet have DNA evidence to back it up. In summary, the roots of the teeth look very Neanderthal, while the neck and tooth crowns of modern humans. Looks more like. ”
The recurrence of mixed lineages could not be determined, but Stinger speculated that this occurred within a few generations of the former. The final test will be DNA analysis of the teeth, which the team plans to do in the future.
“The only other explanation I can think of is for this combination of traits from two species. It is a population that develops a highly unusual combination of traits in isolation,” he said. “However at this time, due to the lower sea level of the last ice age, Jersey was definitely annexed to neighboring France, so that the level of long-term isolation was unlikely.”
Recent dating of sediment at the site suggests that the teeth are about 48,000 years old, which places them about 8,000 years before the extinction of Neanderthals. These archaic humans emerged around 400,000 years ago, and their remains have been found throughout Eurasia. Therefore, La Cotte de St. Species in Brelade are from a late stage of the species. In fact, it was an important time in human history, as early modern humans were spreading throughout Europe and breeding with Neanderthals.
The reasons for Neanderthal extinction are not clear, but theories include violent conflicts with modern humans, disease, climate change (and the inability to adapt), and, as noted, interbreeding. That Neanderthal was absorbed into our species is a detailed plausible explanation.
Certainly Neanderthals can have many different landscapes around the world, ranging from local extinction to extinction of Homo sapiens populations, said Matthew Pope, the study’s co-author and an archaeologist at the UCL Institute . In archeology, it is explained in an email. “Here in La Cotte, we may get a chance to see a closer landscape, through further detailed excavations and scientific analysis.”