Abstract
Compilation of previously discussed main ideas about the evolution of genetic code is presented and completed with bioinformatical analyses of codon usage frequency data from 113 species.It is suggested that the recent 64/20 Genetic Code (Nirenberg) and the associated redundancy in translation developed successively from a much simpler, primitive Code containing only a few AT-rich codons. Codon boundaries were not yet defined so the codons were translated overlappingly. The subsequent addition of GC bases (especially those added at 1st and 3rd codon positions) provided the conditions for the physicochemical definition of codon boundaries and the development of non-overlapping translation. This view is supported by bioinformatics studies in the recent literature as well as by novel findings.
Highlights
The Genetic Code has been known since 1962 [1]
We accept the possibility that the present-day fourbase-type nucleic acids developed from two-base-type molecules; that the current triple code might have been preceded by a one- or two-letter code; and that the current 64 codons have developed from, say, four or sixteen codons
Codons that have been in use for longer are numerically over-represented in the species-specific Codon Usage Tables (CUT)
Summary
The Genetic Code has been known since 1962 [1]. It is largely universal, though some minor variations have been discovered. This consideration suggests that the history of ancient proteins and the function of the primitive Genetic Code might be preserved in non-expressed genomic DNA.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
