Extended Data Figure 5. Detection of point mutations in mice with the BigBlue reporter system.

a, Chromosome 4 of the BigBlue reporter mouse harbours a λ-phage transgene that contains the mutational target. The phage DNA can be recovered from mouse tissues, packaged into phage and used to infect bacteria. Phage cII mutants can be detected by the ability of these phage to form plaques at 24 °C. b, Quantification of the frequency of cII⁻ -mutant phage recovered from the bone marrow of young Aldh2^−/−Fancd2^−/− and control mice carrying the BigBlue transgene. ENU-treated mice serve as positive controls for the assay (P calculated by two-sided Mann–Whitney test; data shown as mean and s.e.m.; n = 7, 7, 6, 7 and 6 mice, left to right). c, Relative contribution of the indicated mutation classes to the point-mutation spectra of cII⁻-mutant phage isolated from the bone marrow. The ENU-mutation spectrum is characterized by T to A transversions and T to C transitions. n is the number of sequenced cII⁻ mutant phage.