The analysis of dinucleotide biases in coding and flanking regions, in
trons, rDNA and repetitive sequences, in the flatworm Schistosoma mans
oni is reported. Except for rDNA, all regions display CpG avoidance an
d TpG plus CpA excess, which might be evidence of the presence of 5mC.
The distribution and hierarchies of dinucleotides differ from the dat
a published for invertebrate and vertebrate coding sequences.