We approach the first step in the evolution of life

The aim of understanding how inert molecules have given birth to life is one more step, according to researchers who have created a system of RNA molecules which can be reproduced in part. They say it should one day be possible to reach a complete self-replication for the first time.

RNA is a key molecule with regard to the origins of life, as it can both store information such as DNA and catalyze reactions such as proteins. Although it is not as effective as one or the other of these elements, the fact that he can do both means that many researchers believe that life has started with RNA molecules capable of reproducing. “It was the molecule that directed biology,” says James Attwater at College University in London.

But the creation of self-reproductive RNA molecules has proven to be difficult. RNA can form double propellers such as DNA and can be copied in the same way, dividing a double propeller in two and adding RNA letters to each strand to create two identical propellers. The problem is that the double RNA propellers remain so strongly that it is difficult to keep the strands separated long enough to allow replication.

Now Attwater and his colleagues have found that the three -letters of RNA letters – tripled – are linked quite strongly to each component to prevent this rezage. Three is the ideal point, says Attwater, because the longer sets are likely to introduce errors. Thus, in the team system, an enzyme of Double Helic form is mixed with triplets.

The solution is made acidic and reheated at 80 ° C (176 ° F) to separate the propeller, allowing Triplets to couple and form the “ladder” of the double propeller. The solution is then made alkaline and cooled at -7 ° C (19 ° F). As the water freezes, the remaining liquid becomes very concentrated and the RNA enzyme becomes active and joins the triplets, forming a new strand.

Until now, researchers have been able to reproduce only up to 30 letters from the 180 -letter RNA enzyme, but they think that by improving the efficiency of the enzyme, they can obtain a complete replication.

Attwater says that the “very simple molecules system” has intriguing properties. One is the possible link between the letters of Triplet RNA and the triplet code used to specify the sequence of proteins in the cells today. “There could be a relationship between the way biology was used to copy its RNA and how biology uses RNA today,” he said.

In addition, the team has noted that the triplets are most likely to be involved in natural replication in the past are those who bind the most. It is believed that the first genetic code was made up of this set of triplets – another intriguing link.

Researchers think that the type of conditions necessary to stimulate this process could occur naturally. As requires fresh water, it is very likely to have occurred on earth, perhaps in a geothermal system.

“The ingredients can be found on earth today – hot sources in Iceland can have mixed pHs, including some as acidic as those we use,” says Attwater.

“The nucleotide triplets of the RNA serve very specific IT functions in the translation in all cells”, explains Zachary Adam At the University of Wisconsin-Madison, which means that they are used to transmit information. “This article is interesting because it could indicate a purely chemical role – a non -computer function – for nucleotide TNN triplets that they could have served before the emergence of a living cell.”