The development of a whole mouse genomic DNA probe coupled to color pigment painting detection methodology can accurately verify mouse micronuclei induced by chemicals or drugs leading to a lower probability of potential artifacts. Using color pigment painting detection of probes in conjunction with Wright's Giemsa counterstain instead of the current fluorescence detection technology ensures low cost, high resolution permanent documentation of slides for a particular test compound. The permanent color pigment-detected micronuclei and adjoining counterstain allows slides to be stored for future analysis without enhancing the signal or adding antifading agents that are associated with fluorescence detection. Combining innovative technology such as fast-in situ hybridization of DNA probes with immunoenzymatic color pigment detection provides rapid verification of true micronuclei (DNA containing) within 2-3 hr.