Overview of mtDNA mutational signatures.

<p>Substitution patterns (mutational signatures) are shown for each cancer type, which each substitution class labeled by the pyrimidine of the Watson-Crick pair [<a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1005333#pgen.1005333.ref031" target="_blank">31</a>] but with sense and antisense patterns shown separately to reveal strand biases. Bars indicate enrichment relative to the expected frequency (observed/expected ratio) for all possible substitutions, taking into account the nucleotide composition of mtDNA and assuming equal probability for all three substitutions. L, light strand; H, heavy strand.