Figure 2. Chromatid-type aberration frequency was analyzed in pairs of isogenic pluripotent and somatic cells exposed to 1 Gy of γ-irradiation at late G2 stage. (A) Chromatid exchanges. (B) Chromatid breaks. Primary foreskin fibroblasts HS27 were used as a reference. *, significant difference was observed as compared with isogenic pluripotent cells, p < 0.0001, X2-test.