Figure 5.

Frequencies of polymorphic substitutions at the immediate first 5′ and 3′ flanking positions of stable G4 loci annotated on the reference strand. Only the frequencies of trinucleotides present at the immediate flanking positions of stable G4 loci were compared with those present at control sequences (trinucleotides present only in control sequences were not considered). A correction for the trinucleotide context was applied (see Materials and Methods). Two-sided Fisher's exact test was used to evaluate significant differences, and P-values were adjusted for multiple testing using Bonferroni correction. An asterisk (*) marks significant differences between G4 and control sequences (adjusted P-value < 0.05).