A sublethal dose of γ-Radiation induced premature aging on the external appearance of all circadian gene-mutant mouse models studied and further increased incidence of tumor and hyperplasia as well as ulcerative dermatitis in Bmal1+/−, Per- and Cry-mutant mice (Fig. 1b, Table 1 and Fig. S1b). Here, PER1 is linked to neoplasm.