Recombination events per chromosome at the indicated chromosomal regions in wild-type and Dnmt-deficient ES cells. (a) Error bars correspond to two independent experiments (n = 2). The total number of C-SCE detected out of the total number of chromosomes analyzed per genotype is also indicated on top of each bar. (b) Representative examples of C-SCE in ES cells of the indicated passage and genotype. Yellow arrows point to the C-SCE event. Bars, 3 μm. (c) T-SCE data were obtained from Gonzalo et al. (2006). (d) Quantification of global SCE events in wild-type and Dnmt-deficient mouse ES cells at the indicated passage number. One culture of each genotype was used for the analysis. The total number of SCE events out of the total number of chromosomes analyzed is indicated on top of each bar. (e) Representative images of SCE events. The arrows indicate chromosomes showing SCE events. Bars, 10 μm. (f) Quantification of C-SCE frequencies in mouse wild-type ES cells and two independent wild-type MEF cells. No significant differences were observed between the indicated cells. Numbers above bars represent total C-SCE events out of the total number of chromosomes counted. (g) Representative CO-FISH images after labeling lagging (red) strand centromeres are shown. Yellow arrows indicate C-SCE events. Bars, 5 μm. Error bars represent standard error.