Evolutionary diversity of reverse (R) fluorescent chromosome bands in vertebrates

摘要: Mitotic chromosomes, interphase cell nuclei, and male meiosis of 41 species representing all vertebrate classes were analyzed with distamycin A/mithramycin counterstaining. The purpose the study was to recognize differences common characteristics in reverse (R) fluorescent banding patterns chromosomes at various stages evolution. In contrast warm-blooded mammals birds, euchromatic segments most reptiles, amphibians, fishes contain no multiple R-bands. This is thought be due absence long homogeneous regions (isochores) DNA cold-blooded vertebrates. Distamycin specifically reveals GC-rich constitutive heterochromatin examined, heterochromatic have opposite staining properties mithramycin quinacrine. Mithramycin labels nucleolus organizer very brightly karyotypes fishes, reptiles but not mammals. lack fluorescence attributed relatively low level redundancy ribosomal their genomes. Studies on meiotic vertebrates show that labeling organizers independent state activity. can confirmed by nucleoli actinomycintreated cells.