Wnt6 is required for maxillary palp but not wing formation. (A) Wnt6 genomic locus showing the knocked-out region (grey area). (B) Wings from Wnt6KO adult males are not altered in size compared to controls. (C-C’) Wnt6KO wings display grossly normal patterning (C) and no obvious planar-cell polarity phenotype (C’). (D-D”) Wnt6KO flies (D’) lack maxillary palps (positions indicated with arrows). Pan-neuronal re-expression of Wnt6 from a UAS transgene using elav-GAL4 in Wnt6KO animals restores maxillary palp formation (D”). The additional ectopic expression in brain and eye discs causes reduced overall head size and rough eyes. Wnt6KO, Wnt6 knockout.