70% of pydtam/pydC5 flies display more than four dorsocentral macrochaetae.
No significant bristle or eye phenotypes are observed in pydC5 homozygotes.
pydC5 embryos display defects in tracheal development including dorsal branch fusion problems, ectopic terminal cells, a lack of fusion cells, and ganglionic branch outgrowth defects. The dorsal branch phenotype is not fully penetrant; 14% of embryos show wild-type tracheal systems, 22% show defects in 1 metamere, 25% show defects in 2-4 metameres and 39% show defects in >5 metameres. Fusion defects are occasionally observed in the lateral trunk, although the penetrance of this is lower than for the dorsal branch.
pydC5/Df(3R)p-XT103 transheterozygotes show the same tracheal phenotypes as pydC5 homozygotes.
pydC5 mutant clones which affect the terminal cells do not affect branch fusion to a significant extent, whereas pydC5 clones that affect the fusion cells are associated with branch fusion defects and rarely show a wild-type branch fusion pattern. Dorsal branches with pydC5 clones show large loops of intercellular adherens junctions, indicating that cell intercalation is not complete. These intercalation defects are not fully penetrant. In most cases, dorsal branches with a cell intercalation phenotype are still able to stretch and eventually reach the dorsal midline, and some can even undergo branch fusion.