High-resolution fluorescencein situ hybridization ofRBM- andTSPY-related cosmids on released Y chromatin in humans and pygmy chimpanzees

Abstract
Applying two-colour fluorescencein situ hybridization (FISH) we simultaneously hybridizedRBM- andTSPY-related cosmids to Y chromosomes in prophase and to released Y chromatin in interphase nuclei of man and pygmy chimpanzee. Whereas, even on prophasic Y chromosomes, no resolution of the overlappingRBM andTSPY signal clusters could be achieved, theRBM andTSPY signals are completely separated from each other in our maximum released Y chromatin stretches in interphase nuclei. These results unequivocally lend support to the view that theRBM andTSPY families have an interspersed organization on the Y chromosomes of man and higher apes. Thus, the distribution ofRBM andTSPY signals might well go back to a common organization of these genes next to each other on an ancient Y chromosome.