Sequential staining with Hoechst 33258 and quinacrine mustard for the identification of human chromosomes in somatic cell hybrids

We have analysed metaphase chromosomes of man-mouse somatic cell hybrids using a sequential staining procedure involving the fluorescent DNA-binding stains, Hoechst 33258 and quinacrine mustard. This was found to be a simple and reliable means of differentiating the chromosomes of the two species and of identifying specific human chromosomes. In addition, this method will permit the study of the segregation of human chromosome homologues that are discordant for quinacrine mustard fluorescent polymorphisms.