Figure 2

Bisulfite treatment. The effects of bisulfite treatment on DNA are shown. An “m” superscript indicates a methylated cytosine. The orientation of each strand is indicated by “<<” and “>>”. Bisulfite treatment converts unmethylated cytosines into uracils and, ultimately, thymines. After PCR, however, a given fragment may have C- > T conversions or G- > A conversions, depending on its orientation relative to its origin fragment.