[Structural polymorphism of the heterochromatin region of human Y chromosome]

A comparison of sequential stained Y-chromosomes from 13 individuals has shown that Q- and C-blocks are not identical. Several polymorphic variants of positively stained regions were revealed. These data suggest the existence of no less than 4 types of structures in the heterochromatic region of Y-chromosome, that vary independently and reflect the localization of different satellite DNA sequences: 1) this region is positively stained using both Q- and C-methods; 2) the proximal Q-negative block, positively stained by C-method; 3) the distal Q-negative block, positively stained by C-method; 4) the distal Q-positive block not revealed by C-method. For the complete revealing of heterochromatic constitution of human Y-chromosome both Q- and C-methods are needed.