title: [Composition and variability of bases in degenerate and non-degenerate positions in codons of various types of mRNA].
abstract: Codon base frequencies have been studied in all published mRNA sequences of more than 50 codons. Bases are not "random" in any codon position. Variability in degenerate position III is of the same order as in the other two positions (non-degenerate). The base distribution in each codon position is significantly different from that in each other position. Position I has the most distinctive make up. Correlations demonstrate that in this ensemble of 1,265 codons positions I and II have the same type of composition as in the decoded mRNA for the average protein.
mesh_terms: D001483:Base Sequence; D003062:Codon; D012333:RNA, Messenger; D012265:Ribonucleotides / Q000032:analysis*; D013223:Statistics as Topic
chemical_list: D003062:Codon; D012333:RNA, Messenger; D012265:Ribonucleotides
vernacular_title: Composition et variabilité des bases en positions dégénérées et non dégénérées dans les codons de quelques mRNA