Research

Artificial intelligence found traces of a lost species in human DNA

Deep in the DNA of Asians is hidden genetichint indicating the existence of an unknown human ancestor. Remarkably, it was not the man who came to this striking hypothesis, but the algorithm of artificial intelligence. Welcome to the archeology of the 21st century. A new study, published last week in Nature Communications, suggests that the hominid, which was not yet discovered, was interbred with modern humans tens of thousands of years ago.

Lost human ancestor?

This mysterious species ended up extinct, butThe 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 descent. A press release issued by the Genome Regulatory Center says that for the first time, deep learning was used to explain the history of mankind, which "paves the way for the application of this technology in other issues in biology, genomics and evolution."

According to a new study, the mysteriousThe hominid is probably a hybrid of Neanderthals and Denis people. Neanderthals who lived in Europe and Denisovans who spread to Siberia, Southeast Asia and Oceania were a closely related group of early humans who separated from a common ancestor about 744,000 years ago. When anatomically modern humans (Homo sapiens) spilled out into Eurasia from Africa, they mingled and interbred with Neanderthals and Denisovians whom we know from genetic research. In addition to the large amount of DNA left by Neanderthals, the scientists extracted Denis's DNA from the 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 Denis people.

However, the latest research shows that modern people, in addition to crossing with Neanderthals and Denis people, crossed with a third, yet unknown species.

This idea is not new. In 2016, genetic research co-authored by Mauch Mondal from the University of Tartu and Jaume Bertrapetita from the University of Pompeu-Fabra provided evidence that the indigenous Australian population from South and Southeast Asia “keeps a small fraction of the pedigree of an unknown extinct hominid, and this pedigree is missing Europeans and East Asians. " Their new research is about finding out where this small share came from.

To this end, Mondal and Bertranpetite presentedevidence in the form of demographic analysis, which was based on deep learning and supplemented by statistical analysis. Their algorithm developed and compared numerous sophisticated demographic models to make predictions about the history of the incest of Eurasia. For 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 histories. Statistical analysis later calculated which of these stories were the most likely.

The team used deep learning toteach the algorithm to “predict human demographics” in the process of hundreds of thousands of simulations, says Oscar Lao, a principal researcher at the Center for National Science and Genetics. “Whenever we conduct a simulation, we travel along a possible path in the history of mankind. With the help of these simulations, deep learning allows us to observe where this pedigree puzzle comes from. ”

Gathering this genetic jigsaw puzzle togetherled to the alleged “third archaic introgression”, meaning the third hybridization event among ancient people (the other two are a genetic mix between modern humans and Neanderthals and modern humans and Denisovskim). Modern people have crossed with an unknown third species, and models show that this is either a Neanderthal-Denisov hybrid, or an early offshoot of the Denisov ancestry.

That Neanderthals and Denis people who havecommon ancestor, could interbreed, no one will be surprised. Last year, scientists found 90000-year-old remains of one such hybrid man - a girl with a Neanderthal mother and a Denis man's father. Due to lack of evidence, scientists were not sure that this was happening on a regular basis. The new study supports the suggestion that two extinct species multiplied often enough to produce a genetically distinguishable hybrid population.

Serena Tucci, ecologist and evolutionary biologist fromPrinceton University used genetic evidence last year to show that early modern humans mated with Denisov populations at least twice. This means that the lingering traces of Denisov's DNA, enclosed in the genomes of the Asians living today, emanate from at least two separate Denisovian populations.

Regarding the assertion about the existence of some unknown human species, Tucci says that it is not worth presuming beyond the available evidence.

Without a doubt, more evidence is needed. However, recent research should encourage archaeologists to look for additional clues that indicate the existence of the alleged species.

As you can see, the use of AI in archeogenetics is very cool. What do you think, where else could these practices be applied? Tell us about it in our chat. in Telegram.