According to the most accepted theory on the origin of life, life began with very simple molecules, RNA chains, which were able to self-replicate. The problem with the theory, however, is that the fragility of these chains when there are replication errors (mutations) made it almost impossible for them to have evolved into more complex life forms. An international team of scientists, including Universitat Autònoma de Barcelona researchers, has discovered that these early molecules were much more resistant than was thought until now. According to the conclusions of the study, they may have developed enough to contain around 100 genes, which is considered to be the minimum quantity required for the most basic forms of primitive life, similar to the bacteria we have today. The research was published in the September edition of Nature Genetics.
In the primordial soup that produced life on earth, there were organic molecules that combined to produce the first nucleic acid chains, which were the first elements able to self-replicate. According to one of the more accepted theories, these molecules were ribonucleic acid (RNA) chains, a molecule that is practically identical to DNA and that today has the secondary role in cells of copying information stored in DNA and translating it into proteins.
These proteins have a direct active role in the chemical reactions of the cell. In the early stages of life, it seems that the first RNA chains would have had the dual role of self-replicating (as is today the case with DNA) and participating actively in the chemical reactions of the cell activity. Because of their dual role, these cells are called ribozymes (a contraction of the words ribosome and enzyme). But there is an important obstacle to the theory of ribozymes as the origin of life: they could not be very large in length as they would not be able to correct the replication errors (mutations). Therefore they were unable to contain enough genes even to develop the most simple organisms.
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