Ancient genome reveals its secrets
In 2010, Svante Paabo from the Max Planck Institute in Leipzig and his colleagues sequenced DNA extracted from a finger bone fragment found in the Denisovskaya Cave in the Altai territory in southern Siberia. They found that the sample belonged to a girl belonging to a previously unknown group of ancient people, called Denisovites. Thanks to a new technology that divides the double DNA chain into two separate strands that can be sequenced separately, the authors analyzed each "letter" of the Denisov genome 30 times. This made it possible to obtain a sequence whose quality is not inferior to the results of sequencing samples obtained from modern humans.
As part of the new study, an international team of scientists, led by Svante Peebo, compared the Denisov genome with the genome of a Neanderthal, as well as with the genomes of 11 modern people living in different parts of the world. The results obtained confirm earlier data, according to which the population of islands in Southeast Asia has a number of common genes with Denisovans. In addition, the genomes of people from East Asia and South America contain slightly more Neanderthal genes than the genomes of Europeans.
Based on the results of comparing the chromosome sequences inherited by the Denisovan girl from her father and mother, the researchers concluded that the genetic variability of Denisovans was much lower than that of modern humans. Apparently, this is due to the fact that the size of the initially small population of Denisovans increased rapidly when they settled in vast territories. The researchers note that if in the future the study of the Neanderthal genome reveals the same model of population size change, it will be possible to say that a single population of people from Africa gave rise to both Denisovans and Neanderthals.
In addition, the list of genetic differences between modern humans and Denisovans turned out to be very long. It includes approximately 100,000 items, some of which relate to genes associated with the functioning of the brain and the development of the nervous system. Others may have influenced the structure and function of the skin, eyes, and morphology of teeth.
According to Peebo, the results of the work carried out will help to find out why there was a sharp increase in both the number and complexity of cultural organization in the population of the ancestors of modern man, while the number of ancient people decreased until their complete disappearance. Earlier this year, Leipzig researchers published the Denisovan human genome sequence online, making it available to the general public.
Article by Matthias Meyer et al. A High-Coverage Genome Sequence from an Archaic Denisovan Individual is published in the journal Science.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of the Max Planck Institute for Evolutionary Anthropology: Ancient genome reveals its secrets.
Portal "Eternal youth" http://vechnayamolodost.ru11.09.2012