Fig. 3

Functional unit-specific selection on tumor somatic mtDNA mutations in coding regions. a Mutation densities (mutation number in a region/region bp length) in different coding regions. b Mutation densities of T, C, A, G bases in different coding regions. c Mutation densities in ATP6 and ATP8 genes. d Mutation densities in functional units of tRNA coding regions. tRNA functional units were shown (Left). Chi-square test was used