A differential staining technique for chromosome identification and its comparison with fluorescence technique

A cytochemical differential staining technique for localizing repetitive DNA in metaphase preparations and quinacrine fluorescent staining of metaphase preparations were used simultaneously, and the methodology is described. An idiogram for the differential staining technique was developed and a comparison of the idiograms of both techniques revealed that the differential staining technique involves primarily the localization of repetitive DNA at or near the centromere, whereas with the quinacrine fluorescence technique nearly the entire length of the chromosome fluoresces to produce characteristic banding patterns. The combined use of these methods can be a valuable tool in the study of human chromosomes and provides a practical aid in the identification of individual chromosomes and the further definition of their structure.