Comment How robust are the models of the origin of life ? Commentary on “ Evolutionary dynamics of RNA-like replicator systems : A bioinformatic approach to the origin of life ”

Charles Darwin derived his principle of natural selection form observations he made in Britain and on his voyage as naturalist on board of HMS Beagle. All his conclusions were derived from studies on higher organisms, animals and plants [1], and yet the principle applies equally well to unicellular organisms, protists, eubacteria and archaebacteria. Even the evolution of viruses, viroids, and molecules in the test-tube is perfectly described by Darwin’s ideas. Moreover, competing computer programs [2] and other objects outside biology follow the rules of natural selection. The Darwinian mechanism sets in whenever biomolecules, cells, organisms, societies, computer devices or other entities capable of reproduction are on the stage and compete for resources. Why is Darwin’s approach almost universal? The answer is simple: Neither details of reproduction nor the nature of the multiplying entities matter in the contest. The only property that counts is the number of progeny in future generations and the genius Charles Darwin recognized this fact through making an enormous abstraction from the wealth of details in the adaptations of species he saw in nature. Extrapolations of Darwin’s principle to pre-cellular life were made ever since the nineteen sixties when the idea of a world of biomolecules optimizing the rate of reproduction in the sense of Darwin was born. Sol Spiegelman’s experiments with RNA molecules [3] and Manfred Eigen’s kinetic theory of evolution [4] provided evidence that adaptation and evolution do not require cellular life. Tom Cech and Sidney Altman discovered that RNA molecules are not only information carriers but can also act as highly specific catalysts [5,6]. Walter Gilbert’s and others postulated the existence of an RNA-world [7], which has preceded the DNA-RNA-protein world we are familiar with. The central idea, in essence, is that RNA molecules are acting as both, information carriers and catalysts, and constitute thereby a sufficiently rich repertoire of functions for evolution. The experimental support for the idea of an RNAworld becomes stronger and stronger, however, a few problems on the way from chemistry towards the origin of life remain still unsolved, among them: (i) how came the first RNA or RNA-like molecules into existence, and (ii) how did the first general replicating enzyme on RNA-basis arise that was able to amplify arbitrary RNA sequences. In the spirit of Leslie Orgel this means if in a chain of events a single one is implausible the entire chain is implausible [8,9]. Although there is an ample body of knowledge on processes that might have been relevant for the origin of life on Earth, we do not know yet whether there has been an RNA-world as a precursor of conventional biological evolution but, nevertheless, it remains an exciting hypothesis and RNA based scenarios are definitely worth being studied by experiment, theory, and computer simulation. Nobuto Takeuchi and Paulien Hogeweg [10] present a comprehensive review on mathematical and computational approaches to early replication and focus on the aspects of creation and processing information under origin of life