Figure 5. The figure shows the hepitypes of at the CpG island at genomic coordinates on chromosome 15 (22,751,474–22,751,613 bp) at the SNRPN (small nuclear ribonucleoprotein polypeptide N) locus for the sample CRC-NT providing an example of an imprinted gene.

In panel A, the hepitype frequencies and an overview of the locus structure is given. Panel B shows a maximum-parsimony tree constructed from hepitypes with a minimum frequency of 1%. The numbered hepitypes from panel A are annotated in the tree. The frequent hepitypes are indicated by grey circles sized according to the relative hepitype frequencies. Panel C summarizes the frequency of methylated and non-methylated sites on the background of the two hepitypes (left completely unmethylated – all T, right – completely methylated – all C) defined by the imprinting of the locus. As detailed in the Results section, single unmethylated sites occur more frequently on the background of the all C hepitype, than single methylated sites on the background of the unmethylated hepitype (p<1×10⁻¹⁵).