Extended Data Fig. 1. Generation of PolgA^mut/mut;Lgr5-creER;Apc^fl/fl and Lgr5-creER;Apc^fl/fl mice and analysis of colonic adenomas.

a: Breeding scheme. MtDNA mutations can be transmitted down the maternal germline⁶⁵ therefore it was essential that only Lgr5-creER;Apc^fl/fl (red) mice from a wild-type PolgA mother used as controls. b: Kaplan-Meier survival curve showing survival time following tamoxifen administration in PolgA^mut/mut mice. Survival to clinical endpoint or experimental endpoint of 60 days is shown, ‘n’ = number of mice. c: β-Catenin immunohistochemistry was performed on colon sections from n=17 PolgA^mut/mut;Apc^fl/fl mice and n=13 Apc^fl/fl mice. Representative images are shown (scale bars 3mm (first column) and 200µm). d: Frequency of adenomas in the colon 23 days post-Apc deletion (unpaired, two tailed, t-test, p=0.7444), n=17 PolgA^mut/mut;Apc^fl/fl mice and n=13 Apc^fl/fl mice, data are mean ±s.d. e: Mean adenoma size in the colon in n=17 PolgA^mut/mut;Apc^fl/fl mice and n=13 Apc^fl/fl mice 23 days post-Apc deletion. All adenomas on a section were quantified ranging from 5 to 280, mean per mouse ± s.e.m are shown. Two-sided linear mixed effect regression model with mouse ID as a random effect, p<0.0001. f-g: Quantification of the frequency of thymidine analogue incorporation in all cells per colonic adenoma (f) and LGR5+ cells per colon adenoma per mouse (g). n=5 mice per group with 18 adenomas analysed per mouse. Mean frequency per adenoma per mouse ± s.e.m is shown. Two-sided linear mixed effect regression model with mouse ID as a random effect, p<0.001. h-i: Apoptotic cells were quantified using (h) cleaved caspase 3 (CC3) immunohistochemistry n=7 PolgA^mut/mut;Apc^fl/fl mice and n=9 Apc^fl/fl mice and (i) TUNEL labelling (n=9 mice per group) in mice 23 days post-Apc deletion. A minimum of 10 adenomas were analysed per mouse, mean percentage of apoptotic cells per adenoma per mouse ±s.e.m is shown. Two-sided linear mixed effect regression model with mouse ID as a random effect, CC3 p=0.0092, TUNEL p= 0.002. * p<0.05, **p<0.01, ***p<0.001.