The Df(3L)eyg^C1 chromosome does not act as a dominant suppressor of telomeric silencing (assayed using the effect of the chromosome on the eye colour phenotype of flies carrying "P{w^var}KR3-2", a stable "brown-red" variant of the P{3'WP-2,w^var}2Lt insertion).

The number of finger-like sensillae of the antennal organ is reduced in homozygous embryos and the sensillae only rarely reach full length. The salivary duct primordium forms normally in homozygous embryos but is unable to complete the first convergence and extension and instead remains as two clumps of cells. Later, the duct cells move anteriorly in a process resembling wild-type, although they do not obviously converge towards the ventral midline. Approximately 75% of embryos have no individual salivary ducts, and the remaining 25% have only one individual salivary duct which is almost always malformed. A common salivary duct sometimes forms in these embryos, sometimes appearing broader than wild-type. Homozygotes die as embryos.