| It is pretty certain that the first life did not use any kind of genetic material, because that is impossible. When RNA or any other kind of genetic material first appeared, the first thing that must have been possible to do with it was to copy it, a.k.a. to replicate it. If the genetic material was used first to do anything useful, e.g. to control protein synthesis or to catalyze directly any useful reaction, that genetic material would have disappeared immediately, because it could not be replicated. So the first genetic material must have been able of being replicated without doing any useful function, therefore is was actually an RNA virus. The useful functions must have appeared later and then the genetic material was integrated as an essential part of the living beings, allowing a much faster evolution towards levels of complexity that would have been impossible to reach without having a genetic material. To be able to replicate the first genetic material, there must have already existed some life forms able to exploit an energy source to reproduce themselves. You have noticed a correct analogy, exactly like the control automaton of a CPU, which can be either hard-wired, having a dedicated structure that cannot be easily changed to perform other functions, or it can be microprogrammed, using a control memory, whose content can be easily rewritten to implement a very different CPU, a self-reproducing living being can use genetic material, in which case it can easily evolve into a different living being, or it may use no genetic material, but consist, like how it seems to be said in Gánti's work, of which I was not aware until now, by a cycle of reactions, where in each reaction some cell component assembles another cell component, until the last component, which assembles the first component. Such a living being, without a genetic material, could not evolve easily, because almost any change would have damaged the cycle of reactions, most likely stopping the reproduction. Regarding RNA, before the first RNA molecule was ever assembled, the existing life forms must have been using ATP and the other nucleotides as dehydrating agents able to condense smaller molecules into larger molecules, e.g. for creating peptide bonds. Therefore ATP (with some of it current uses) is certainly older than RNA. The polymerization of nucleotides into RNA must have been initially an undesirable side reaction consuming the useful nucleotides. |