Deep in the DNA of Asians hidden genetic clue indicating the existence of an unknown ancestor of man. What is remarkable, this amazing hypothesis came not a man, and the algorithm of artificial intelligence. Welcome to 21st century archaeology. A new study published last week in Nature Communications suggests that as yet undetected hominid has been interbred with modern humans tens of thousands of years ago.
The lost ancestor of man?
This mysterious species eventually died out, but AI, developed by scientists from the Institute of evolutionary biology and several other European institutions, found traces of its existence in the DNA of modern people of Asian origin. A press release issued by the center for genome regulation States that, for the first time, deep learning was used to explain human history, which “paves the way for the application of this technology to other issues in biology, genomics and evolution.”
According to a new study, the mysterious hominid is probably a hybrid of Neanderthals and denisovs. The Neanderthals who lived in Europe, and the denisovs who spread to Siberia, Southeast Asia, and Oceania, were a closely related group of early humans separated from a common ancestor about 744,000 years ago. When anatomically modern humans (Homo sapiens) evolved in Eurasia from Africa, they mingled and interbred with Neanderthals and denisovans, which we know from genetic research. In addition to the large amount of DNA left behind by the Neanderthals, scientists extracted Denis ‘ DNA from a well-preserved finger bone found in a Siberian cave. Today we find traces of these extinct species in the DNA of non-African people, although only Asians have preserved the genetic heritage of the denisovs.
However, the latest research shows that modern people, in addition to crossing with Neanderthals and Denisov people, crossed with the third, yet unknown species.
This idea isn’t new In 2016, a genetic study co-Mauja Mandala of the University of Tartu and Jaume of Bertranpetit from the University Pompeu-Fabra has provided evidence that the indigenous Australian population from South and South-East Asia “holds a small fraction of the ancestry of an unknown extinct hominid, and this lineage is absent in Europeans and vostochnaia”. Their new research is devoted to finding where this small share came from.
To this end, Mondal and Bertranpetit presented evidence in the form of demographic analysis, which was based on in-depth training and supplemented by statistical analysis. Their algorithm has developed and compared numerous complex demographic models to make predictions about the history of incest in Eurasia. To do this, scientists fed the algorithm a whole dish of genome sequences derived from both modern and ancient DNA, which allowed the neural network to create a large set of possible demographic stories. Statistical analysis further calculated which of these stories were most likely.
The team used deep learning to teach the algorithm to “predict human demographics” in hundreds of thousands of simulations, says Oscar Lao, chief researcher at the Center for national science and genetics. “Whenever we run a simulation, we travel the possible path in human history. With these simulations, deep learning allows us to see where this pedigree puzzle comes from.”
Putting together this genetic mosaic led to the supposed “third archaic introgression”, meaning the third event of hybridization among ancient people (the other two being the genetic mixture between modern humans and Neanderthals and modern humans and denisovs). Modern humans have interbred with an unknown third species, and models show that it is either a Neanderthal-Denisov hybrid or an early branch of the Denisov pedigree.
The fact that the Neanderthals and Denisov people who have a common ancestor could cross, will not surprise anyone. Last year, scientists found 90,000-year-old remains of one such hybrid man — a girl with the mother of a Neanderthal and the father of a Denisov man. Due to lack of evidence, scientists were not sure that this was happening on a regular basis. The new study supports the assumption that two extinct species reproduce frequently enough to produce a genetically distinct hybrid population.
Serena Tucci, an ecologist and evolutionary biologist at Princeton University, last year used genetic evidence to show that early modern humans mated with Denis populations at least twice. This means that the lingering traces of Denisov DNA contained in the genomes of Asians living today, comes from at least two separate Denisov populations.
As for the allegation of the existence of some unknown human species, Tucci says there is no need to assume beyond the available evidence.
No doubt, more evidence is needed. However, recent research should encourage archaeologists to look for additional clues indicating the existence of the alleged species.