Aneuploidy assays on interphase nuclei by means of in situ hybridization with DNA probes

A method has been developed to detect chemically induced aneuploidy in interphase nuclei by means of in situ hybridization with chromosome-specific DNA probes. Lymphocyte cultures were treated with two known aneuploidy inducers, Benomyl and Griseofulvin. Two DNA fragments, QP23 and Y97, homologous to repetitive sequences, localized in the pericentromeric region of chromosome 9 and in the centromeric region of Y chromosome respectively, were used as probes. Following autoradiography, grain clusters, revealing the presence of the target chromosomes, were scored in resting nuclei. A marked increase in the frequency of cells with supernumerary autoradiographic signals was observed with both probes at all concentrations of the test compounds. The assay procedure appeared to be reproducible, sensitive and efficient in scoring large cell samples. It may therefore provide a useful tool for preliminary screening of potential aneuploidy inducers.