A team from the SCRIPPS Institute in California came to the conclusion that the molecules of deoxyribonucleic acid (DNA) and ribonucleic acids (RNA), contrary to conventional wisdom, could appear on Earth at one and the same time. Until now it was assumed that RNA arose much earlier, and DNA was formed based on them.
RNA contained in the cells of all living organisms. Like DNA, they represent a long chain of nucleotides which in turn consist of three components — nitrogenous base, ribose sugar and a phosphate group. The main difference between them is that the deoxyribonucleic acid is a double helix (or, more precisely, double screw), while RNA is a single chain of polynucleotides. According to most scientists, that RNA were the first capable of reproducing itself macromolecules in history. Subsequently, they are RNA molecules was created proteins and enzymes, which, in turn, helped the RNA to produce DNA, which led to the formation of complex organisms.
Getting to the study, the researchers suggested that if DNA really came from RNA, it should be possible to “cross”. As specialists suggest, the resulting molecule would represent a sort of a kind of “intermediate link” between ribonucleic and deoxyribonucleic acids. If such a molecule was stable, it could serve as an argument in favor of the fact that the Earth really was the “RNA world”, and then the events developed by the above scenario. However, the “hybrid” molecules turned out to be much less viable, regardless of whether elements of the integrated DNA into RNA, or Vice versa.
Today if a fragment of ribose randomly integrates into the DNA chain, a mistake corrected by special enzymes, which hardly existed at the dawn of the emergence of life. According to scientists, all this suggests that DNA would not be able to “gain a foothold” in the RNA world, losing stability due to the ingress of alien fragments. From this the researchers conclude that looks much more logical scenario in which DNA and RNA arose at about the same time and developed “in tandem”.
The scientists published their work in the journal Angewandte Chemie.