Q-bands in Lilium and their relationship to C-banded heterochromatin

In L. pardalinum, narrow bands of quinacrine fluorescence are distributed throughout the chromosomes. These vary in intensity from dull to bright, and their constant pattern allows all chromosomes to be recognized. Bright bands occur at some centromeres, and near all three nucleolar constrictions. In L. longiflorum, similar Q-bands occur along chromosomes, but they are less distinctive and their pattern does not closely match that of L. pardalinum. Also, L. longiflorum does not have bright regions at or near primary and secondary constrictions. Most Q-bands do not coincide with dark Giemsa C-bands, except for the bright nucleolar and centromeric regions in L. pardalinum. All C-banded heterochromatin stains identically after SSC pretreatment, dark with Giemsa and bright with quinacrine.- The many Q-bands of varying intensity, wide distribution and constant pattern, unrelated to C-bands, may be analogous to mammalian Q-bands. Such universality is expected if Q-bands area fundamental component of chromosome architecture.