The Coevolution Theory of the Origin of the Genetic Code

Giulio, Massimo Di

doi:10.1007/pl00006464

Cited by 45 publications

(21 citation statements)

References 8 publications

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“…19 and 20 but see ref. 31), these same critical analyses (19,20) confirmed that the choice of precursor-product pairs strongly influences the statistical significance of this result.…”

Section: Criticism Of Coevolution Theorysupporting

confidence: 61%

“…A very different theory, called code coevolution, holds that the organization of the canonical code reflects the historical pathways by which amino acid biosynthesis evolved at the dawn of life (3,(12)(13)(14)(15)(16)(17)(18)(19)(20). The theory postulates that the earliest genetic code used a small number of prebiotically synthesized amino acids (21), and subsequently expanded to its present form by incorporating novel derivatives of these primordial amino acids as metabolic (biosynthetic) pathways evolved.…”

mentioning

confidence: 99%

“…Although the general idea of code expansion originated much earlier (1) and has appeared in many forms (see refs. 4, 20, 22, and 23 for selective reviews), coevolution theory has gained the widest acceptance by proposing an explicit pathway of code evolution that apparently had strong statistical support (3,19,20). Specifically, a central tenet of coevolution theory is that a ''product'' amino acid synthesized from a precursor amino acid usurped codons previously assigned to this precursor, such that the sequence of steps by which the code expanded is visible within modern codon assignments (Fig.…”

mentioning

confidence: 99%

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Testing a biosynthetic theory of the genetic code: Fact or artifact?

Ronneberg

Landweber

Freeland

2000

Proc. Natl. Acad. Sci. U.S.A.

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Here we re-examine the biochemical basis of this theory to test the validity of its statistical support. We show that the theory's definition of ''precursor-product'' amino acid pairs is unjustified biochemically because it requires the energetically unfavorable reversal of steps in extant metabolic pathways to achieve desired relationships. In addition, the theory neglects important biochemical constraints when calculating the probability that chance could assign precursor-product amino acids to contiguous codons. A conservative correction for these errors reveals a surprisingly high 23% probability that apparent patterns within the code are caused purely by chance. Finally, even this figure rests on post hoc assumptions about primordial codon assignments, without which the probability rises to 62% that chance alone could explain the precursor-product pairings found within the code. Thus we conclude that coevolution theory cannot adequately explain the structure of the genetic code.

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“…19 and 20 but see ref. 31), these same critical analyses (19,20) confirmed that the choice of precursor-product pairs strongly influences the statistical significance of this result.…”

Section: Criticism Of Coevolution Theorysupporting

confidence: 61%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Testing a biosynthetic theory of the genetic code: Fact or artifact?

Ronneberg

Landweber

Freeland

2000

Proc. Natl. Acad. Sci. U.S.A.

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“…Pretran synthesis, whereby a precursor amino acid while bonded to its tRNA is converted to a product amino acid, furnished an important mechanism for the entry of some Phase 2 amino acids into the code. The advantage of pretran synthesis is that the nascent product immediately receives the anticodons on the tRNA (Wong 1975a(Wong , 1981(Wong , 2005aDi Giulio 2004). Accordingly, the basic tenets of CET are:…”

Section: Tenets Of Coevolution Theorymentioning

confidence: 99%

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

Wong

2007

Orig Life Evol Biosph

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The coevolution theory proposes that primordial proteins consisted only of those amino acids readily obtainable from the prebiotic environment, representing about half the twenty encoded amino acids of today, and the missing amino acids entered the system as the code expanded along with pathways of amino acid biosynthesis. The isolation of genetic code mutants, and the antiquity of pretran synthesis revealed by the comparative genomics of tRNAs and aminoacyl-tRNA synthetases, have combined to provide a rigorous proof of the four fundamental tenets of the theory, thus solving the riddle of the structure of the universal genetic code.

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“…The sequence of the amino-acids from left to right in Figure 5 follows their order.of origin. Among them, Gly (without chirality), Ala, Ser, Asp, Glu and Val are the earliest amino-acids [25,26] . The rate of the earliest L-amino acids being selected stands at 90.00% and that of the D-amino acids stands at 10.00%.…”

Section: Resultsmentioning

confidence: 99%

A new theoretical model for the origin of amino acid homochirality

et al. 2007

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Amino acid homochirality, as a unique behavior of life, could have originated synchronously with the genetic code. In this paper, phosphoryl amino-acid-5'-nucleosides with P-N bond are postulated to be a chiral origin model in prebiotic molecular evolution. The enthalpy change in the intramolecular interaction between the nucleotide base and the amino-acid side-chain determines the stability of the particular complex, resulting in a preferred conformation associated with the chirality of amino acids. Based on the theoretical model, our experiments and calculations show that the chiral selection of the earliest amino acids for L-enantiomers seems to be a strict stereochemical/physicochemical determinism. As other amino acids developed biosynthetically from the earliest amino acids, we infer that the chirality of the later amino acids was inherited from the precursor amino acids. This idea probably goes far back in history, but it is hoped that it will be a guide for further experiments in this area.

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The Coevolution Theory of the Origin of the Genetic Code

Cited by 45 publications

References 8 publications

Testing a biosynthetic theory of the genetic code: Fact or artifact?

Testing a biosynthetic theory of the genetic code: Fact or artifact?

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

A new theoretical model for the origin of amino acid homochirality

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