Mammoth and Elephant: Find a million differences
Mice with mammoth DNA
Department of Science "Newspapers.Ru" tells about what happened to mice whose DNA acquired the mammoth gene, and whether the achievement of researchers will help to resurrect an extinct animal.
An international team of researchers led by Vincent Lynch from the University of Chicago conducted deep sequencing of the mammoth genome and compared the results with the genetic information of modern relatives of the animal – Asian and African elephants. The full text of the scientists' work can be found in the journal Cell Reports (Lynch et al., Elephantid Genomes Reveal the Molecular Bases of Woolly Mammoth Adaptations to the Arctic, in open access).
The researchers analyzed the genomes of two woolly mammoths that lived about 20-60 thousand years ago. The woolly mammoth appeared on our planet 200-300 thousand years ago in Siberia and spread from there to Europe and North America. The height of these animals was not much higher than the height of modern elephants, ranging from 2.8 to 4 m, but the physique of mammoths was much more massive: their weight, according to scientists, could reach 8 tons.
Woolly mammoths were perfectly adapted to the harsh climatic conditions of their habitats: with low temperatures, they were helped to cope with tough, up to 90 cm long, wool and dense undercoat, under which there was a layer of fat up to 10 cm thick. Vincent Lynch and his colleagues, comparing the genome sequencing data of the mammoth and its modern relatives, elephants, were able to identify unique genetic mechanisms that allowed mammoths to adapt to cold and harsh climates.
A group of researchers managed to find 1.4 million variants of various genes characteristic exclusively for the mammoth, which changed the proteins produced by 1,600 other genes.
Unique genetic features were responsible for the adaptation of the animal to a cold climate, encoding lipid metabolism (biochemical and physiological processes for processing and transporting fats), the development of skin and wool, the mammoth's perception of ambient temperature, as well as the biological rhythms of the body. According to the researchers, all this helped the mammoths feel good in conditions of constant low temperatures and short daylight hours.
Geneticists paid special attention to a group of genes responsible for the body's sensation of air temperature and the development of the skin and wool of the body. With the help of special technologies, scientists were able to recreate an ancient version of the TRPV3 gene and transplant it into the cells of the human body. As a result, the cells began to produce a protein that reacted to heat worse than its modern counterpart. However, the researchers were not satisfied with these conclusions and went even further, changing the TRPV3 gene in the body of laboratory mice to a variant characteristic of mammoths. As a result, the mice began to show a preference for cold, striving to spend time not in warm rooms, but in cool enough ones. The hair of rodents has also undergone changes – it has become longer and wavy.
Diagram from an article in Cell Reports – VM.The success of Vincent Lynch's research group is certainly a breakthrough in the study of mammoths.
Is it worth taking it as another step on the way to the resurrection of an extinct species, rumors and conversations about which have become especially popular in the last few years? According to Lynch himself, his work is primarily aimed at studying the molecular evolution of ancient animals, and not their resurrection, although theoretically the scientist does not consider this unattainable: "I believe that over time we will get the technical ability to do this. However, the question here is whether it is worth implementing such a project. I personally think not. Mammoths are extinct, and the environment in which they lived is also no more. There are many animals that are on the verge of extinction, and we have to save them."
However, getting even the technical possibility of resurrecting a mammoth in the near future seems unlikely. "Newspaper.Ru" has already told about the project of cloning a woolly mammoth, which is being carried out by Yakut scientists together with Hwang Woo Suk, a notorious geneticist from South Korea. Hwang Woo-suk has already been caught falsifying scientific data: a little more than a decade ago, he announced the creation of the world's first cloned human stem cells. However, it later turned out that the geneticist had manipulated the results of the experiments, and the stem cells were the result of photomontage.
Despite the fact that Hwang Woo Suk's articles were withdrawn from scientific journals, and he himself received a suspended sentence, a few years ago his reputation was restored: the geneticist received a patent for working with stem cells in the United States (however, this decision caused misunderstanding of Western scientists).
Russian experts in the field of paleontology and genetics believe that cloning a mammoth is impossible, if only because the probability of detecting an entire DNA molecule in the remains of a mammoth tends to zero, and the "transformation" of the elephant genome into the mammoth genome is a technically impossible task.
But, even considering the utopian plans for the resurrection of the mammoth, the study of the features of its DNA will continue: according to scientists, in the process of trying to bring the animal back to life, geneticists and paleontologists will be able to make many important and useful discoveries.
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06.07.2015