Chemists have confirmed the simultaneous appearance of DNA and RNA at the dawn of life

Chemists and molecular biologists synthesized the nucleosides of DNA and RNA from the same components, reported in Nature. This shows that nucleic acids of both types could have formed at the same time, not sequentially (first RNA, then DNA), as did some supporters of the theory of RNA world.

To transmit genetic information, you need to copy (replicate) bearing its molecules — DNA and RNA. RNA maintains its own replicationand for copying DNA desired enzymes DNA polymerase. Are proteins, and they can appear only if the corresponding RNA molecules. The latter is theoretically able to act as a source of information on the composition of the DNA polymerases, and as a catalyst for their education. Biological system in which there is only RNA, but no DNA can reproduce itself and the system with DNA, but no RNA — no. Therefore, a number of biologists believes that first there was RNA-objects, and then there’s DNA and there was a division of functions: the RNA remains a matrix for protein synthesis and catalyst, and DNA became the custodian of the information. The hypothesis of RNA world, in which developing these views, in recent years, finds a lot of evidence.

However, it is not clear how deoxyribonucleic acid was separated from RNA, as they existed in the first time. DNA and RNA are assembled from nucleotides — small molecules of sugar ribose or its derivative deoxyribose, a nitrogenous base and a phosphate group (phosphate group if no, the connection is called a nucleoside). The nucleotides in DNA and RNA are different: the first in the ribose by one oxygen atom less than that of the second, also in DNA may be the nitrogen base thymine, but not uracil (in RNA). Reaction of synthesis of these nucleotides require different conditions, and this is an argument in favor of the fact that DNA “evolved” from RNA and coexisted and likely coevolutional with her.

Researchers from the UK and Poland, headed by John Crescendos (John Sutherland) from the University of Cambridge checked out, could be simultaneously synthesized nucleosides of DNA and RNA. In 2009, they already tried to create “building blocks” of nucleic acids from hydrogen cyanide and other simple molecules under the action of ultraviolet light and foundthat the formation of nucleosides do not have to collect them from sugar and a nitrogenous base. In those experiments have turned out compounds with ribose and a pyrimidine in structure — anhydroglucose, stages with free ribose and the nitrogenous bases was not. Scientists have now analyzed which of the intermediate products obtained in the reactions, and tried to synthesize them on the basis of deoxyribonucleoside.

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