a, ISC proliferation during ageing in males. b, ISC proliferation during ageing in females. Note that ISCs in females proliferate more than those in males regardless of age and genetic background. c, Females have more mitotic ISCs per gut (left), bigger guts (middle) and more mitotic ISCs per unit area (right) than males regardless of age. Progeny from crosses between female Oregon R and male w1118 were used for this analysis. d, Male progeny from crosses between Oregon R and w1118 have the same autosomes but different sex chromosomes. e, The male progeny with endogenous white exhibit ageing-induced ISC proliferation but those without white do not. f, Male progeny from crosses between Oregon R and w1 were used to examine ISC proliferation during ageing. g, w1 Oregon R flies do not demonstrate ISC dysregulation during ageing. h, Paraquat or DSS induces comparable ISC proliferation in Oregon R and wOregon R flies. Statistical significance was determined using two-tailed unpaired t-test (a, b, e, f, g), two-tailed Mann Whitney test (c) and one-way ANOVA with Dunnett’s post-test (h).