Photo: Tomas Bravo / Reuters
A group of scientists under the leadership Willerslev Eske (Eske Willerslev) from the University of Copenhagen, found traces of hepatitis b in human DNA, who lived about 4.5 thousand years ago. It is the oldest evidence of the existence of the virus found so far. The results of the study publication reports Science Alert.
Experts have identified the DNA from the teeth and the temporal bone of the skeletons of 137 people from nomadic peoples who lived 200-7000 years ago. To do this, the biologists used a technique called shotgun, when a long chain of DNA is split into overlapping fragments, which are then embedded in the vectors of ring molecules copier in bacterial cells. This creates a genomic library. Randomly selected fragments sequeiros, that is determined by the sequence of nucleotides, after which they combined to form larger chains.
This method allows biologists to compare the newly deciphered DNA sequences with known contained in the databases. In addition, were analyzed the genomes of 167 people, sequenced in another study. 25 people, one of whom lived 4.5 thousand years ago, there were fragments of the nucleic acid belonging to the genome of hepatitis b virus, which is able to fully or partially embedded in the DNA of the host.
Before this discovery the age of the earliest signs of a hepatitis b virus was 450 years. The results show that the infection was widespread in Eurasia for several thousand years.
According to the Centers for control and prevention of diseases of the United States, every year from hepatitis b die of 786 thousand people around the world.
Video, photo All from Russia.