MutationMotif

MutationMotif analyzes point mutation influences using log-linear models and sequence logo-style visualizations to characterize how neighbouring bases and sequence context affect mutation spectra across genomic contexts.

Key Features:

• Log-Linear Analysis of Neighbourhood Base Influences: MutationMotif employs log-linear analysis to assess how neighbouring bases impact mutation occurrences, identifying motif extent and variability across samples.
• Sequence Logo Representation: It generates sequence logo-like visualizations that represent the influence of neighbouring bases on mutation types.
• Mutation Spectra Analysis: The tool applies log-linear analysis to mutation spectra—the relative proportions of different mutation directions from a starting base—and visualizes these distributions with logo-like displays.
• Comparative Genomic-Context Analysis: MutationMotif enables comparison of mutation spectra across genomic contexts (for example, autosomes versus the X-chromosome), highlighting differences such as the dominance of T→C transitions on the X-chromosome.

Scientific Applications:

• Human germline mutation analysis: MutationMotif recapitulates the CpG effect, identifies major neighbourhood influences typically within ±2 bases of the mutating base, and detects motifs such as a significant A→G-associated motif.
• Malignant melanoma mutation analysis: The method confirms melanoma-specific features including strand asymmetry and distinct neighbouring influences compared to other contexts.
• Comparative studies across species, cell types, and genomic locations: It supports analysis of mutational processes across different biological species, cell types, and genomic locations by contrasting mutation spectra and motifs.

Methodology:

Uses log-linear models that explicitly examine sequence motifs affecting point mutations, estimate motif size and variability between samples, and produce sequence-logo-like visualizations.