C(1)DX/Df(Y)bb-465 males (in which the Df(Y)bb-465 chromosome is the only source of rDNA as C(1)DX lacks bb) show a bobbed mutant phenotype.
Df(Y)bb-465 is a suppressor of the position effect variegation (PEV) at the w locus seen in the In(1)wm4 chromosome.
Salivary gland nuclei of C(1)DX/Df(Y)bb-465 males have a reduced nucleolar volume compared to controls, and the nucleoli often appear fragmented, with ectopic small or micro nucleoli being seen.
The PEV at the lt locus seen in the T(2;3)ltX13 chromosome is enhanced by Df(Y)bb-465.