The heterochromatin bands were obtained after modification of standard procedure. The modification eliminated or greatly reduced treatment in 0.2 N HCL, and prolong treatment in Ba(OH)2.8H20, in decreased temperature of Ba(OH)2.8H2O and 2xSSC.
M. Rozek, Department of Experimental Zoology, Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland, e-mail: rozek@isez.pan.krakow.pl