[Linear differentiation of the human Y-chromosome].

During the final 5.5th to 7th hr of the cycle in presence of BUdR, the human Y-chromosome was delayed in its mitotic condensation in the distal part of the long arm. This part was not homogeneous by the degree of the delay. The unevenly condensed Y-chromosome stained with quinacrine was brightly fluorescent in its stretched part. The fluorescence seemed to correlate with the degree of stretching. The distal part of the long arm was heavily labeled with H3-deoxycytidine thus demonstrating presence of late replicating DNA with GC-base pairs.