‘Super-archaic’ man paired with the primitive ancestor of both Denisovans and Neanderthals 700,000 years ago
- Researchers used special software to compare the DNA of ancient human fossils
- They also discovered that Denisovans and Neanderthals broke up 600,000 years ago
- This is a much older estimate of the divergence of the species than previously suggested
Researchers conclude that a “super-archaic” human paired with the primitive ancestor of both Denisovans and Neanderthals 700,000 years ago.
This was the earliest known episode of crossbreeding between different populations of old people – and concerned the most distant related species.
The “super-archaic” people separated from all other people in the evolutionary tree about two million years ago.
Experts had used special software to investigate human evolution history based on genetic evidence found in fossils in the Spanish Sima de los Huesos cave.
The algorithm also concluded that Denisovans and Neanderthals were different species 600,000 years ago – much earlier than previously thought.
A model developed by the same researchers in 2017, on the other hand, had suggested that the two species parted 381,000 years ago.
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Researchers conclude that a “super-archaic” human paired with the primitive ancestor of both Denisovans and Neanderthals 700,000 years ago. Pictured, the researcher’s model of the history of human evolution. The colored lines between the branches represent episodes of crossing and the transfer of genes between the different human species
The team’s new model supports the view that modern people and their ancestors only spread three times from Africa to Eurasia.
These migrations are thought to have taken place about 1.9 million years ago with the superarchists, 700,000 years ago for the ancestors of Neanderthal-Denisovan and 50,000 years ago for modern people.
Large-brained hominids first appeared in Europe and Asia about 600,000 years ago, in the period known as the Middle Pleistocene – which was an important milestone for early humans.
To shed light on this period in human evolution, anthropologist Alan Rogers of the University of Utah and colleagues have considered eight models with different genetic combinations that may be the result of crossbreeding between early hominids.
They also include data from Neanderthals from the Altai Mountains of Siberia and the Vindija Cave in Croatia, as well as from modern Europeans.
“We have never been aware of this crossover episode and we have never been able to estimate the size of the super-archaic population,” said Professor Rogers.
“We only shed light on an interval in human evolutionary history that was completely dark before.”
“These findings about the timing at which crossover took place in the human line tell something about how long it takes for reproductive isolation to develop,” he added.
The algorithm also concluded that Denisovans (photo) and Neanderthals were already different species 600,000 years ago – much earlier than previously thought
‘Our [statistical] software ignores the component within the population of genetic variation. For this reason, it is not affected by recent changes in population size, which often interfere with attempts to study a deep history, “Professor Rogers added.
“In fact, we have cleaned up a part of the brush that often conceals the view of the distant past.”
The full findings of the study were published in the journal Science is progressing.
Experts had used special software to investigate human evolution history based on genetic evidence found in fossils in the Spanish Sima de los Huesos cave
WHO WERE THE DENISOVANS?
The Denisovans are an extinct species of people who seem to have lived in Siberia and even in Southeast Asia.
Although the remains of these mysterious early people have only been discovered in one location – the Denisova Cave in the Altai Mountains of Siberia, DNA analysis has shown that they were widespread.
DNA from these early people is found in the genomes of modern people in a large area of Asia, suggesting that they once covered a wide range.
DNA analysis of a snippet finger bone in 2010, (pictured) that belonged to a young girl, revealed that the Denisovans were a species akin to, but different from, Neanderthals.
They are thought to be a sister species of the Neanderthals, who lived in West Asia and Europe around the same time.
The two species seem to have separated themselves from a common ancestor about 200,000 years ago, while they separated from the modern human Homo sapien lineage about 600,000 years ago.
Bone and ivory beads found in the Denisova cave were discovered in the same sediment layers as the Denisovan fossils, which led to suggestions that they had advanced tools and jewelry.
DNA analysis of a fragment of a five-digit finger bone in 2010, which belonged to a young girl, showed that it was a species that was related to, but different from, Neanderthals.
Later genetic studies suggested that the ancient human species separated from the Neanderthals somewhere between 470,000 and 190,000 years ago.
Anthropologists have now wondered whether the cave had been a temporary shelter for a group of these Denisovans or whether it had formed a more permanent settlement.
DNA from molar teeth from two other individuals, an adult male and a young female, showed that they died in the cave at least 65,000 years earlier.
Other tests have suggested that the young woman’s tooth could be as old as 170,000 years.
It is thought that a third molar belonged to an adult man who died about 7,500 years before the girl whose little finger was discovered.