EXTENT OF POLYTENY IN THE PERICENTRIC HETEROCHROMATIN OF POLYTENE CHROMOSOMES OF PSEUDONURSE CELLS OF OTU (OVARIAN TUMOR) MUTANTS OF DROSOPHILA-MELANOGASTER

In the polytene nuclei of germ-line cells (ovarian pseudonurse cells) of Drosophila melanogaster females mutant for otu11 (ovarian tumor), t he pericentric heterochromatin is much more abundant than in somatic s alivary gland cells. This is due to the degree of heterochromatin comp action (and consequently the level of underreplication) being lower in the nurse cells than in the salivary gland cells. The lower level of compaction probably results in a very low degree of position effect ge ne inactivation in the ovarian nurse cells.