Scientists have found an RNA molecule that self-replicates under certain conditions, potentially explaining the origin of life on Earth

British scientists have discovered a miniature RNA molecule that can copy itself. The discovery may explain how life arose on Earth from nonliving matter.

Philip Holliger's team from the UK Medical Research Council's Laboratory of Molecular Biology found the QT45 molecule, consisting of just 45 nucleotides. The results of the work were published in the journal Science.

The researchers analyzed a library of 12 trillion random RNA sequences, looking for fragments that could act as polymerase, the builder of molecules. The selected candidates were put to the test of survival: they had to create ever longer chains in increasingly difficult conditions. QT45 turned out to be the most effective.

In experiments simulating the early Earth, the molecule demonstrated the ability to replicate itself. In a salt mixture of ice crystals and liquid, QT45 synthesized a complementary RNA strand and then used it as a template to create a new copy.

As noted in the work, the discovery is important for understanding the origin of life. Most scientists believe that life began with the appearance of a molecule capable of spontaneously copying itself. The RNA world hypothesis suggested that it was RNA, but the known ribozymes are too large and complex to arise by chance in the primordial soup.

The study authors point out that if such a small molecule performs complex tasks like self-replication, life's progenitor molecules may be much more common than previously thought. This means that the origin of life is probably not a unique event, but a natural process under suitable conditions.

Earlier, an international team of researchers presented evidence that RNA molecules could have formed naturally about 4.3 billion years ago. The work described a six-step process for synthesizing RNA from simple organic compounds, which could occur without any outside intervention.