Figure 2From: Modelling mutational and selection pressures on dinucleotides in eukaryotic phyla –selection against CpG and UpA in cytoplasmically expressed RNA and in RNA virusesObserved / expected CpG and UpA frequencies in (A) human DNA and (B) mRNA sequences as a function of G+C content. Frequencies of each dinucleotide predicted from mutational models with 1, 2 and 4 parameters (1p, 2p and 4p, labelled according to the inset box) were superimposed on observed distributions of CpG and UpA dinucleotides (blue and red dots respectively; see inset box). Quadratic lines of best fit through observed distribution (black lines) were matched to model predictions over a G+C composition range from 20%-80%.Back to article page