Question 6: Coevolution Theory of the Genetic Code: A Proven Theory

Wong, J. Tze‐Fei

doi:10.1007/s11084-007-9094-1

Cited by 33 publications

(29 citation statements)

References 28 publications

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“…This intrinsic code mutability with respect to the amino acid alphabet provides strong support for the occurrence of active early code expansions at the dawn of life as the code coevolved with amino acid biosynthetic pathways that brought new amino acid building blocks to proteins to enhance their functions [20]–[24]. Therefore the chemical versatility of the amino acid alphabet underwritten by the universal genetic code was not the outcome of fortuitous happenstance but the result of nature's relentless search for excellence in protein performance.…”

Section: Discussionmentioning

confidence: 93%

Genetic Code Mutations: The Breaking of a Three Billion Year Invariance

2010

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The genetic code has been unchanging for some three billion years in its canonical ensemble of encoded amino acids, as indicated by the universal adoption of this ensemble by all known organisms. Code mutations beginning with the encoding of 4-fluoro-Trp by Bacillus subtilis, initially replacing and eventually displacing Trp from the ensemble, first revealed the intrinsic mutability of the code. This has since been confirmed by a spectrum of other experimental code alterations in both prokaryotes and eukaryotes. To shed light on the experimental conversion of a rigidly invariant code to a mutating code, the present study examined code mutations determining the propagation of Bacillus subtilis on Trp and 4-, 5- and 6-fluoro-tryptophans. The results obtained with the mutants with respect to cross-inhibitions between the different indole amino acids, and the growth effects of individual nutrient withdrawals rendering essential their biosynthetic pathways, suggested that oligogenic barriers comprising sensitive proteins which malfunction with amino acid analogues provide effective mechanisms for preserving the invariance of the code through immemorial time, and mutations of these barriers open up the code to continuous change.

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Section: Discussionmentioning

confidence: 93%

Genetic Code Mutations: The Breaking of a Three Billion Year Invariance

2010

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“…The formation of amino acids by biosynthetic pathways guided the development of the genetic code (Di Giulio, 2008;Wong, 2007;Wong, 2005;Wong, 1975). An extension of this theory (Di Giulio, 2008) states that the first amino acids came from biochemical pathways directly originating from sugar degradation.…”

Section: Population Of the Genetic Code: The Coevolution Theorymentioning

confidence: 99%

The evolution of the genetic code: Impasses and challenges

Kun

Radványi

2018

Biosystems

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The origin of the genetic code and translation is a "notoriously difficult problem". In this survey we present a list of questions that a full theory of the genetic code needs to answer. We assess the leading hypotheses according to these criteria. The stereochemical, the coding coenzyme handle, the coevolution, the four-column theory, the error minimization and the frozen accident hypotheses are discussed. The integration of these hypotheses can account for the origin of the genetic code. But experiments are badly needed. Thus we suggest a host of experiments that could (in)validate some of the models. We focus especially on the coding coenzyme handle hypothesis (CCH). The CCH suggests that amino acids attached to RNA handles enhanced catalytic activities of ribozymes. Alternatively, amino acids without handles or with a handle consisting of a single adenine, like in contemporary coenzymes could have been employed. All three scenarios can be tested in in vitro compartmentalized systems.

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“…This postulate is such as to remove the majority of the non-contiguities between the amino acids in a precursor-product relationship (Wong, 1975). That this postulate is most likely correct is suggested by the existence of the pathways AsptRNA Asn →AsntRNA Asn (Curnow et al, 1996) and Glu-tRNA Gln →Gln-tRNA Gln (Schon et al, 1988), which are molecular fossils of the codon concession mechanism from the precursor to the product amino acids, as predicted by the coevolution theory (Wong, 1975(Wong, , 1976(Wong, , 2005(Wong, , 2007Wachtershauser, 1988;Danchin, 1989;de Duve, 1991;Di Giulio, 2002. Therefore, the fact that this set of precursor-product pairs gives a non-significant probability is explained by the very behaviour of Asp and Glu, which are also involved in the transformation taking place on tRNAs, for the very reason that the codons AAY and CAR might have codified for Asp and Glu in the late phase of genetic code evolution.…”

Section: Resultsmentioning

confidence: 99%