The fact of the genetic similarity between certain human species and Neanderthals may seem shocking to some. Nevertheless, many scientists do believe that the genes of modern Europeans and Asians contain from one to four percent of the DNA that they received from Neanderthals.
For a long time, scientists have tried to find evidence that this similarity is the result of crossing between Homo sapiens and Neanderthals. And so, the other day, a group of European scientists declares that thanks to statistical modeling, they have found evidence that there really was a sexual relationship between a man and a Neanderthal.
In the past, research on the similarities between Neanderthals and Homo sapiens has most often looked at two possible scenarios. On the first, the idea was proposed that a certain kind of people - those who later became modern Eurasians - developed in certain isolated areas of Africa.
This allowed them to retain a genetic similarity to the Neanderthals after they split from their common ancestor. The theory of interspecific crossing, on the other hand, claims that sexual relations between two species (Neanderthal and Homo sapiens) took place after Homo sapiens migrated from Africa.
To find out which of these theories is closest to the truth, scientists decided to investigate both using statistical data and an evolutionary model.
“We ran colossal math calculations to figure out the plausibility of each of these scenarios,” said Laurent Franz, an evolutionary biologist at the University of Weningen in the Netherlands and co-author of the new study.
“The calculations were carried out as follows: we divided the genome into small blocks of the same length and based on them we created a genealogy model,” the expert continues, pointing out that it was this method that allowed them to say with a higher degree of confidence that interspecies relations really took place.
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"Our analysis shows that the model describing interspecies relationships is more plausible than the one that relies on established African roots."
Scientists say that the second scenario is indeed also possible, but "it cannot by itself explain the genetic similarity of species."
The results of the new study, published in the scientific journal Genetics, effectively dispute a 2012 study published in the journal Proceedings of the National Academy of Sciences, which pointed to the impossibility of interspecies crossing.
“It seems to me that someone made a mistake in that job. When we tested both theories, we got strong support for the scenario that describes the crossbreeding between human and Neanderthal."
Scientists initially tested their statistical research method by studying the genetic history of insect and pig populations in Europe and Southeast Asia. However, they later realized that such a model can be applied to the study of interspecies relationships, when there is only a limited reserve of genetic material. Moreover, Franz believes that the results of their research (like the results of previous ones) should finally put an end to the dispute about the cruelty of some species over others in the process of evolution.
“There was a lot of evidence as to what actually happened to those species. Some believe that some hominid species killed and drove out other species, but as our research shows, not everything is as simple as it seems at first glance,”the scientist shares.
“Apparently, some Neanderthals were still able to assimilate within some populations of intelligent people and shared shelter with them,” the researcher continues.
Therefore, to think that a person tried to destroy everything that was different from his kind is at least partially a wrong opinion. The scientist is sure that the process of human evolution was much more complicated and confusing than previously thought.
