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COMMON BUNKUM. “We often hear in the scientific and even popular press that the ‘genetic code’ of some organism has been ‘cracked’ by genomics, which is of course total nonsense. The genetic code is not the nucleotide sequence of the genome, but rather the set of rules by which those nucleotides are translated into amino acids and by extension genes into proteins.“ https://www.sciencedirect.com/science/article/pii/S0960982216309174 View in LinkedIn

SHEER LUCK. “It is tempting to think that a system so central to life should be elegant, but of course that’s not how evolution works; the genetic code was not designed by clever scientists, but rather built through a series of contingencies.” https://www.sciencedirect.com/science/article/pii/S0960982216309174 View in LinkedIn

THE FOUR INTO TWENTY. “The genetic code is a concept that captured the imaginations and drove much of the research of the first molecular biologists; almost immediately after the description of the double helix some very elegant models for how 4 ‘letters’ of DNA could encode 20 letters of protein were proposed.” https://www.sciencedirect.com/science/article/pii/S0960982216309174 View in LinkedIn

OTHER PLAYERS. “Phylogenetic analysis of translation system components, in particular aminoacyl–tRNA synthetases, shows that, at a stage of evolution when the translation system had already attained high fidelity, the correspondence between amino acids and cognate codons was determined by recognition of amino acids by RNA molecules, i.e., proto-tRNAs.” http://www.annualreviews.org/doi/abs/10.1146/annurev-genet-120116-024713 View in LinkedIn

FIDELITY IS A BY-PRODUCT. “The structure of the standard genetic code is nonrandom and ensures high robustness of the code to mutational and translational errors. However, this error minimization is most likely a by-product of the primordial code expansion driven by the diversification of the repertoire of protein amino acids, rather than a direct result of selection.” http://www.annualreviews.org/doi/abs/10.1146/annurev-genet-120116-024713 View in LinkedIn

WHY IT IS UNIVERSAL. “The universality of the code likely results from the combination of a frozen accident, i.e., the deleterious effect of codon reassignment in the standard genetic code, and the inhibitory effect of changes in the code on horizontal gene transfer.” http://www.annualreviews.org/doi/abs/10.1146/annurev-genet-120116-024713 View in LinkedIn

SELECTIVE PRESSURES. “The genetic code is not quite universal. The rare variations that we know of reveal selective pressures on the code and on the translation machinery. New data suggest the code changes through ambiguous intermediates and that termination is context dependent.“ https://www.sciencedirect.com/science/article/pii/S0960982216309174 View in LinkedIn

SELECTIVE PRESSURES. “The genetic code is not quite universal. The rare variations that we know of reveal selective pressures on the code and on the translation machinery. New data suggest the code changes through ambiguous intermediates and that termination is context dependent.“ https://www.sciencedirect.com/science/article/pii/S0960982216309174 View in LinkedIn

SECONDARY VARIATIONS. “The standard genetic code is virtually universal among extant life forms. Although many deviations from the universal code exist, particularly in organelles and prokaryotes with small genomes, they are limited in scope and obviously secondary.” https://lnkd.in/ddaxciH View in LinkedIn

NOT OPTIMAL. “However, the standard genetic code is far from being optimal because, given the enormous overall number of possible codes (>10(84)), billions of variants are even more robust to error.” http://www.mdpi.com/2075-1729/7/2/22/htm View in LinkedIn