The results of the works carried out in the Laboratory of Molecular Cy
togenetics (Institute of Cytology and Genetics of Siberian Branch of t
he RAS, Novosibirsk) devoted to the molecular genetic analysis of main
units of polytene chromosomes,(1) bands, interbands, and puffs, as w
ell as intercalary and pericentric heterochromatin,(2) are summarized
. The results are discussed in terms of the dynamic model of organizat
ion of polytene chromosomes.