Tuesday , May 18 2021

The first genes can be mixed DNA and RNA forms



Deoxyribonucleic acid, DNA, is the molecular carrier of genetic information. The chemical is very similar to ribonucleic acid, RNA, which only fills this task in viruses and is otherwise responsible for various other functions. Although RNA is also a very complex molecule, it is somewhat simpler than DNA and can not only transmit information but also catalyze chemical reactions.

The beginning of life based on RNA

In addition, despite its similarity, one molecule can not convert into another purely chemical route. That is why today most people start with the so-called RNA world hypothesis. Therefore, the first necessary forms of life based on the more versatile RNA, and later transferred to a more stable DNA storage medium.

Ramanarayanan Krishnamurthy of the Scripps Research Institute of California, who is also involved in the present study, and his colleagues showed in 2017 the possibility of a common occurrence of RNA and DNA. Dithiophosphate was probably already present on the "prebiotic" soil at a time when there was no form of life. This molecule can link building blocks of RNA and DNA into longer chain threads.

The usual building blocks of RNA and DNA

Together with John Sutherland's team from the Medical Research Council in Cambridge, researchers around Krishnamurthy identified another key component. 2-thiouridine could also be present in a still uninhabited country and served to build the information carrier. Researchers have shown that this compound is not just a precursor of building blocks of RNA, but can also react in several chemical steps to form a building block of DNA.

Thus, the ability to gain more space not only to RNA, but to RNA and DNA is included in the first form of life. Scientists even suggest that the first genes were still a mixture of RNA and DNA. Although organisms with these properties are unknown today, it was only recently possible to produce artificial bacteria with such mixed genes.

Neither new theory of mixed forms could speak against today's division of work between RNA and DNA, because even though they were together at the beginning of life, they quickly and quickly shared their advantages and disadvantages: DNA for long-term preservation of genetic information of RNA for their tasks , such as short-term storage and transfer of information, as well as protein production. "In our research area we begin to realize that RNA and DNA can be originally confused, but later separated into their specialties," concludes Krishnamurthy.


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