Fig. 1

5-FU induces context dependent T>G mutations in vitro. a Schematic overview of the experimental setup used to determine the 5-FU mutation spectrum in two independent human small intestinal organoid experiments. 6.25 μM 5-FU was added to isogenic organoids for 3 days, followed by a 4-day rest period. This cycle was repeated 5 times. Subsequently, organoids were made single cell and expanded further into clonal organoids to obtain sufficient DNA for WGS. Controls were cultured in 5-FU-free medium. The WGS data of the original isogenic organoid line served as reference sample. b The experimentally derived mutation spectra from 5-FU treated organoid lines (upper) and untreated organoid lines (middle). Each spectrum shows the mutation probability of each indicated context-dependent base substitution type. The spectrum below shows the difference between the 5-FU (positive values) and the in vitro (negative values) mutation spectrum