Sequencing in Siberia
Siberian biologists have become participants in a new genomic project
Scientists of the Institute of Molecular and Cellular Biology SB RAS will take part in an international project on sequencing the genomes of all types of eukaryotes, that is, living organisms whose cells contain a nucleus – this was told by the Deputy director of the IMKB SB RAS for scientific work, Doctor of Biological Sciences Alexander Sergeevich Grafodatsky at the opening of the II All-Russian Conference "High-performance sequencing in genomics".
"The Smithsonian Institution in the USA and the Chinese Beijing Genomics Institute (BGI) have become the leading organizations in this project, but all other participants are working as best they can," Grafodatsky said. – The total number of eukaryotes known today is 1,700,000 species, so we are facing a very bold task. I'm sure we can handle the sequencing.
Academician Dmitry G. Knorre, one of the founders of the Institute of Chemical Biology and Fundamental Medicine of the SB RAS, co-organizer of the event, also made a welcoming speech at the opening of the conference:
– I am a living witness of the giant path that world and Russian science has taken from the question "What is DNA?" to real sequencing, – said Dmitry Georgievich. – For the first time in our country, it was conducted in the laboratory of the famous Soviet biochemist Alexander Baev, deciphering an RNA molecule in which only about 80 nucleotides, and already today sequencing the complete genome becomes the subject of practical activity. This is a huge breakthrough, but now we face new challenges.
The essence of the work of molecular biologists is as follows: back in the 1970s, so-called methods of differential chromosome coloring appeared, based on the ability of some dyes to bind specifically to specific areas of chromosomes, depending on their organization. This was of great importance both for medicine (it became easier to identify pathologies) and for comparative cytogenetics – scientists were able to compare individual sections of chromosomes of different species, to find a connection between them. At the same time, it was impossible to compare these areas in humans and, for example, in a ferret or a pig: they had moved too far apart during evolution. More precise molecular methods were needed – this was fluorescent in situ hybridization (or chromosomal painting). It allows you to divide all the chromosomes of the genome on a special sorter, that is, put them in a test tube, and then use them as a molecular sample, label them with fluorochromes (a fragment of a molecule that gives it fluorescent properties) and try to find homology. Today it is used to find similarities between different species.
– Unfortunately, there have never been good cultivars in Russia and they are unlikely to appear soon, they are too expensive, – says Alexander Sergeevich. – Nevertheless, we cooperate with English, American and Chinese laboratories that can provide us with this equipment: thanks to this, we have the richest collection in the IMKB SB RAS sorted samples that none of these organizations have separately.
Sequencing of all eukaryotes is far from the first ambitious project involving Siberian biologists. According to Alexander Grafodatsky, acquaintance with this topic is connected with the international "Human Genome". At the time of its creation in 1988-1989, Russia was a competitive power. Formally, the work continued for quite a long time, but for our country it ended a couple of years after it began due to the collapse of the USSR. Nevertheless, the project provided an opportunity to meet many interesting people and professionals, to create a foundation for further research.
Despite the fact that science has stepped forward, today there are very few (about twenty) species for which the same work would be done as for humans, that is, the genome is completely sequenced and structured. Following "The Human Genome Project" in 2009, another one appeared – "Genome 10K", the purpose of which was to sequence the genomes of ten thousand vertebrate species. Researchers of the IMKB SB RAS were among its participants – they engaged in the study of mammals.
"The co–author of one of our articles, Nobel laureate Sidney Brennar, compared the Human Genome to Gutenberg's edition of the Bible, and our new project is to create a huge library where everyone can find any information they need," says Alexander Grafodatsky.
Another problem faced by scientists was the lack of materials for work: there were not so many species for which there were samples of at least some tissue so that DNA could be extracted from them, and even more so there was no cellular fibroblast culture, that is, living tissue cells. However, a small amount was enough for the first studies, and over time the sample base began to be replenished with many, even rare specimens.
A tool like chromosome painting allows scientists to make discoveries that were impossible before. For example, in Africa there is a group of mammals that for a long time could not be attributed to any particular order - it was considered part of insectivores (such as moles, hedgehogs, shrews). They are really similar to each other, but studies of chromosomes have shown that these animals are not relatives. The mammals that formed the afroteria group actually have much more in common with the elephant. That is, the small elephant shrew, which got its name only because of the shape of the movable nose, turned out to be a direct relative of the largest land animal. And scientists of the IMKB SB RAS confirmed that artiodactyls, such as camels, deer, hippos and giraffes, are in the same group with cetaceans – now they are usually allocated to one group.
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26.06.2017