Fig. 6: mtDNA copy number in somatic cells and mtDNA in cancer.
From: Mitochondrial DNA mosaicism in normal human somatic cells
a, mtDNA copy number distributions among 31 individuals, sorted by tissue type, then by age in ascending order. Black dots and red bars represent clones (n = 2,096) and mean values, respectively. b, Read-depth of the mitochondrial genome showing large deletions in two colorectal clones (HC06-14 and HC21-16). Yellow lines represent the deleted regions. c,d, Mutation number (c) and SVAF (d) in normal colorectal clones (blue) and matched colon cancer tissues (red) are correlated with the number of mitotic turnovers across 19 donors. The age of donors is shown in parentheses. Vertical lines indicate the range across clones in each donor. Red and blue lines represent regression lines. e, The proportion of truncating mtDNA mutations within normal colorectal clones and colorectal cancer tissues. Two-sided Fisher’s exact test. f, Distributions of mtDNA copy numbers in normal colorectal clones and matched cancer tissues among 19 individuals. Boxplots illustrate median values with IQRs and whiskers (1.5× IQR). g, The linear correlation between tumor cell fraction and mtDNA copy numbers per diploid nuclear genome in cancer tissues. The gray line and the shaded area represent the regression line and its 95% confidence interval, respectively. Copy number values at 0% and 100% tumor cell fractions are shown by extrapolation. Pearson’s correlation coefficient and P value are provided. Two-sided Pearson’s correlation. TME, tumor microenvironment.
