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A scenario on the stepwise evolution of the genetic code / 基因组蛋白质组与生物信息学报·英文版
Genomics, Proteomics & Bioinformatics ; (4): 143-151, 2007.
Article in English | WPRIM | ID: wpr-317016
ABSTRACT
It is believed that in the RNA world the operational (ribozymes) and the informational (riboscripts) RNA molecules were created with only three (adenosine, uridine, and guanosine) and two (adenosine and uridine) nucleosides, respectively, so that the genetic code started uncomplicated. Ribozymes subsequently evolved to be able to cut and paste themselves and riboscripts were acceptive to rigorous editing (adenosine to inosine); the intensive diversification of RNA molecules shaped novel cellular machineries that are capable of polymerizing amino acids-a new type of cellular building materials for life. Initially, the genetic code, encoding seven amino acids, was created only to distinguish purine and pyrimidine; it was later expanded in a stepwise way to encode 12, 15, and 20 amino acids through the relief of guanine from its roles as operational signals and through the recruitment of cytosine. Therefore, the maturation of the genetic code also coincided with (1) the departure of aminoacyl-tRNA synthetases (AARSs) from the primordial translation machinery, (2) the replacement of informational RNA by DNA, and (3) the co-evolution of AARSs and their cognate tRNAs. This model predicts gradual replacements of RNA-made molecular mechanisms, cellular processes by proteins, and informational exploitation by DNA.
Subject(s)
Full text: Available Index: WPRIM (Western Pacific) Main subject: Base Composition / DNA / RNA / Molecular Sequence Data / Chemistry / Amino Acid Sequence / Sequence Homology, Amino Acid / Evolution, Molecular / Eosinophil Cationic Protein / Genetic Code Type of study: Prognostic study Language: English Journal: Genomics, Proteomics & Bioinformatics Year: 2007 Type: Article

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Full text: Available Index: WPRIM (Western Pacific) Main subject: Base Composition / DNA / RNA / Molecular Sequence Data / Chemistry / Amino Acid Sequence / Sequence Homology, Amino Acid / Evolution, Molecular / Eosinophil Cationic Protein / Genetic Code Type of study: Prognostic study Language: English Journal: Genomics, Proteomics & Bioinformatics Year: 2007 Type: Article