Genetic portrait

Scientists managed to distinguish Neanderthals from microbes

Swedish scientist Svante Peebo, head of the department of genetics at the Leipzig Institute of Evolutionary Anthropology. Max Planck, claims that his group has managed to develop a method with which in the near future it will be possible to completely decipher the genetic code of Neanderthals, mammoths and cave bears. Now such a reconstruction poses great difficulties, despite the large number of fossil remains. Researchers have a hard time distinguishing DNA fragments from extinct humans and animals from the DNA of the bacteria that digested them.

Scientists have long been able to isolate genetic material from preserved tissues of mammoths and our extinct ancestors. But at the same time, not whole molecules fall into their hands, but only their fragments of different sizes. In addition, in semi-decomposed remains, even if they are removed from the layers of permafrost, various microbes are always present. More precisely, not even microbes, but “fragments” of single-celled microorganisms that lived in the tissues of a dead body. Therefore, for genetic analysis, they obtain a cocktail of DNA from different biological species. And since the genome of both humans, cave bears, and protozoa is built from the same nucleotide bricks, it is very difficult to figure out which creature the pieces found belonged to during life.

As Svante Peebo stated, his team managed to develop a technique that will distinguish one DNA from another, AP reports. In addition, geneticists have learned to determine exactly how this long molecule was destroyed and in what places the nucleotide chains broke. Finally, a procedure was created with which it is possible to prevent the “contamination” of the historical genome with traces of the DNA of the researchers themselves: it happens that the biomaterial of modern people working with fossil remains inadvertently ends up in the sample being studied and further confuses the whole picture.

According to the Swedish specialist, this will “make it technically possible” to create a reliable transcript of the genetic sequence of Neanderthals. This is not the first time Peebo and his colleagues have announced this ambitious goal: last fall, the Leipzig team reported that they were able to identify about a million DNA bricks from this extinct branch of people. At the same time, it was suggested that a “draft version” of the Neanderthal genome, consisting, according to scientists, of 3.2 billion nucleotide pairs, could be created within two years.

One of the main mysteries of Homo Sapiens Neanderthalensis, which intrigues not only scientists, but also the idle public, is usually considered the degree of their relationship with modern people Homo Sapiens Sapiens. Now geneticists suggest that the separation of these branches of humanity began about 700 thousand years ago, and the subspecies finally diverged 350-370 thousand years ago. For a very long time, Neanderthals and our ancestors existed on the planet in different regions, with virtually no communication with each other. Competition between populations arose only when Cro-Magnons arrived in Europe, inhabited by Neanderthals. They displaced their distant relatives approximately 24 thousand years ago.

There is an assumption that during a short period of cohabitation in Europe, close subspecies of people could interbreed with each other. It is considered somewhat dubious - nevertheless, over tens of thousands of years, certain changes could not help but accumulate in the DNA. However, according to a group of American and European scientists, which included Svante Peebo, the genomes of Neanderthals and modern humans are at least 99.5% similar. But in order to finally confirm or refute the hypothesis that subspecies of the genus Homo Sapiens not only competed, but were also capable of producing common offspring, Neanderthal DNA needs to be deciphered, which they promise to do soon at the Leipzig Institute.

Vladimir DZAGUTO