Fig. 2. A mathematical model of the fundamental elements underlying a mutational spectrum.

The context-specific mutational probability associated with a mutational process (i.e., mutational spectrum) can be reconstructed from context-specific lesion formation, lesion repair and lesion mutagenic bypass probabilities, in a given genetic background. For each sequence context i, the mutational probability ms_i reflects the product of the probabilities that the lesion forms in that sequence context (p^p_i), the lesion persists (i.e., avoids repair) in that sequence context (p _i), and the lesion miscodes (i.e., introduces a mutation) in that sequence context (p^m_i).