2007/01/16 by Eugene V. Koonin, Koonin, Eugene V.
Physics and Astronomy · Biochemistry, Genetics and Molecular Biology · #Origins and Evolution of Life #Space Science and Extraterrestrial Life #Evolution and Genetic Dynamics
paper · pdf · doi:10.48550/arxiv.q-bio/0701023
Evolution of life on earth was governed, primarily, by natural selection, with major contribution of other evolutionary processes, such as neutral variation, exaptation, and gene duplication. However, for biological evolution to take off, a certain minimal degree of complexity is required such that a replicating genome encodes means for its own replication with sufficient rate and fidelity. In all existing life forms, this is achieved by dedicated proteins, polymerases (replicases), that are produced by the elaborate translation system. However, evolution of the coupled system of replication and translation does not appear possible without pre-existing efficient replication; hence a chicken-egg type paradox. I argue that the many-worlds-in-one version of the cosmological model of eternal inflation implies that emergence of replication and translation, as well as the major protein folds, by chance alone, as opposed to biological evolution, is a realistic possibility and could provide for the onset of biological evolution. Hence an RNA world, as it is currently conceived, might have never existed although catalytic activities of RNA were, probably, critical for the onset of biological evolution and its early stages.