C-BANDING PLUS FLUOROCHROME STAINING SHOWS DIFFERENCES IN C-BAND, G-BAND AND R-BAND IN HUMAN AND MOUSE METAPHASE CHROMOSOMES

C-banded slides stained with DAPI or chromomycin A(3) show different b anding patterns between human and L929 mouse cell line metaphase chrom osomes, which are also different from those obtained with standard Gie msa C-banding or fluorochrome staining. Human metaphase chromosomes pr etreated for C-banding and stained with DAPI show simultaneous C- and DA-DAPI banding patterns, whilst the mouse metaphase chromosomes show both C-banding and G/Q banding like patterns. However, the chromomycin A(3) staining of pre-C-banded metaphase chromosomes reveals conspicuo us R-banding in man that is absent in mouse. Chromatin species-specifi c structural factors would explain these results, which prevent simple comparisons of R-, G-, and C-bands among different organisms. The mar kers induced by this technique may be of practical use for chromosome identification in human-mouse somatic cell hybridization cultures.