A scientist from Germany discovers the secrets of the "Denisovites"
Following the footsteps of the symposium in Altai
Max Planck (Leipzig, Germany), gave an interview to journalists of Russian publications, including the Center for Public Relations of the Siberian Branch of the Russian Academy of Sciences, which kindly provided RIA Siberia with this interesting material. Printed without abbreviations.
– Mr. Paabo, first of all, tell me, how true is the general statement about the discovery in Altai of a previously unknown species of the predecessor of Homo Sapiens of the modern type?
- Yes. This is a new type of human ancestor who was somewhat related to the Neanderthals and lived here in Denisova Cave. I believe that the genetic data clearly show that such a separate group existed. We have not heard any objections about this.
– In the Denisova cave, new finds were discovered not so long ago – teeth and a fragment of a cranial bone, presumably belonging to the same species. Have you started researching them yet?
– We have already published the results on the morphology of one tooth found. They show that this find is very different from both Neanderthals and modern humans. The second tooth, according to DNA analysis, belongs to a Neanderthal, but in morphology it is not comparable to either the Neanderthal or the modern type.
– It is generally believed that individuals of different species do not interbreed or do not give offspring at the same time – for this, in particular, they are classified as a separate species. Now we come to the conclusion that genetically different human ancestors could mix. How does one compare to the other?
– We formulate our conclusions very, very carefully and do not call this or that type of Homo Sapiens precursor a separate biological species. We say "group" or "form" of a person. In particular, because genetic studies have established that representatives of these groups mixed with each other, the "drift of genes" has been proven. Also, we are not in a hurry to assign a separate Latin name and do not use the term Homo Altaiensis. Another form, a group of people, is the most correct formulation. The same approach applies to Neanderthals, and to other lines of Homo development.
– Is it possible to judge how much more archaic the "Denisov people" are than us or Neanderthals, if this branch separated earlier from the further line of development of these groups?
– As far as we understand, Homo Erectus (Homo Erectus – ed.) separated from the common line earlier, and later – Neanderthals together with "Denisovans". It is possible that the latter mixed with Homo Erectus, but this has not yet been proven, there are only some indirect indications on this score. In this case, the results of the mixing should, in our opinion, have some archaic features.
– Do the genetic differences between ancestral human species look more or less in comparison with the differences among modern people of different races and peoples? Was the difference between the genomes of a "Denisovan" and a Neanderthal comparable to the difference between, for example, a Frenchman and a Bushman?
– The distance between the preceding types of Homo is much greater than between different populations of modern humanity. Let me remind you that the presence of a Neanderthal in the genome of our contemporaries averages 2.5%. That is, the Neanderthal is our ancestor by only 2.5%. At the same time, its genetic proximity to the "Denisovan" and other early types of Homo is much greater. After all, both the "Denisovan" (earlier) and the Neanderthal (later) separated from the line along which the formation of modern man went on, although they left their mark in his genome in different ways.
– A lot of bone remains of a hominid from the island of Flores did not provide material for genetic research. And a piece of the phalanx of the little finger from Denisova Cave made it possible to isolate both mitochondrial and nuclear DNA for sequencing. What properties do tissues need to preserve in order to isolate DNA from it? What conditions should this fabric be in?
– The fabric should be kept in a cold, dry atmosphere and not in an acidic environment. And in Indonesia it is very hot and very humid, so the DNA in the tissues has not been preserved. First of all, the amount of material needed to obtain a DNA sample depends on the environment of residence. It is best to have fragments of a long bone, and that it is dense enough. Then, perhaps, 50-100 milligrams of the source material will be quite enough.
– You have already said that it is impossible to restore the morphology of an individual based on the genomic series alone. And is it possible to reconstruct its other properties – gender, age, predisposition to any pathologies?
– There are groups of my colleagues in the USA, in particular, Peter Borham from Stanford, who are just dealing with the immunobiological data of ancient people. Their results have not yet been published, but they believe that the genes of both "Denisovans" and Neanderthals had adaptive significance, therefore, in particular, they spread in parallel with modern human populations. If their immunity had been weakened, or the genetic picture showed a clear tendency to any diseases, they would not have developed this way.
– What else can be "pulled out" of the genome, other than the relationship of its carrier with other communities and the geographical picture of their distribution?
– In the future, when we better understand the functions of the entire genome, we will be able to get much more information from it. But now, if you look, for example, at the genome of Svante Paabo, the most concrete thing that can be said about his appearance is to name the hair color. By the way, it has been established that some Neanderthals were red-haired.
Portal "Eternal youth" http://vechnayamolodost.ru07.05.2013