Usage of the four YR dinucleotides at the TSS. The proportional use of each YR dinucleotide at the representative TSSs was calculated for the three promoter groups: ascidian (A), human CpG-poor (B), and human CpG island promoters (C). Dinucleotides other than CpA, CpG, TpA, and TpG were ignored in this analysis. Whereas CpG is the second most often used dinucleotide in human CpG-rich promoters, the dinucleotide is used least in ascidian and human CpG-poor promoters.
Okamura et al. BMC Genomics 2011 12(Suppl 3):S7 doi:10.1186/1471-2164-12-S3-S7