Only a few kn^KN2 homozygous mutants survive to late embryonic stages.

kn^KN2 mutant clones display defects in several aspects of class IV ddaC neuron structure. Class I, II, and III da neuron structure appears unaffected. In mutant clone ddaC class IV kn^KN2 neurons, the average overall dendrite length is significantly reduced to 32% of wild-type. Dendrite branching is also reduced, to approximately 33% that of wild-type. In addition, the total area covered by the dendritic arbor is significantly reduced to 58% of wild-type.

kn¹/kn^KN2 mutants exhibit 59% more uncovered areas of dendritic outgrowth compared to wild-type ddaC neurons.

kn¹/kn^KN2 ddaC neurons exhibit a significant reduction in dendrite termini to 77% of wild-type levels. In addition there is a polarization of the normally symmetrical class IV dendritic arbor. In mutant neurons about 70% of the dendrite termini are concentrated in the region dorsal to the cell body.

kn¹/kn^KN2 mutant ddaC neuronal clones display a marked reduction of dendrite outgrowth and branching, with tufts of short terminal dendrite branches at the ends of the main branch segments often being visible. The termini are concentrated nearer to the cell body than in wild-type.

kn¹/kn^KN2 mutants do not survive into late embryonic stages.

Homozygous kn^KN4 consistently exhibit head defects. They lack ventral arms and have foreshortened lateralgrate.

Embryonic segmentation is normal. Transheterozygotes with kn¹ enhance the kn¹ wing vein phenotype, the veins are extensively fused. This loss of intervein region reduced the length and width of the wings by 80-90%. The transition point between socketed and unsocketed bristles at the wing margin is shifted posteriorly to the shifted position of wing vein L3. Germline clones give rise to fully viable offspring when outcrossed to kn⁺ sperm and does not alter the larval lethality when fertilised with kn^KN1, kn^KN2, kn^KN3 or kn^KN4 sperm. Clones generated in adult cuticle are normal unless induced in the anterior compartment of the wing in the intervein region between veins L3 and L4. Clones obey the A-P compartment boundary but when they are induced along the boundary the result is an ectopic or shifted vein with an associated loss of vein L4 in the non-mutant posterior compartment. Clones located at the wing margin generated terminal vein 3 bristles rather than true marginal bristles. Doubly mutant mosaic clones with ptc^S2 are very similar to clones mutant for ptc^S2 alone that affect global organisation: reorganisation of the wing when induced in the anterior compartment and clones induced near the anterior margin induce a complete duplication of the anterior wing blade. The kn mutant affects local alteration in wing patterning associated with ptc inactivation.

kn^KN2/kn¹ has larval dorsal multidendritic neuron ddaC | somatic clone phenotype, enhanceable by ct^UAS.cPa/Scer\GAL4^ppk.PG

kn^KN2/kn¹ has dendrite | somatic clone phenotype, enhanceable by ct^UAS.cPa/Scer\GAL4^ppk.PG

kn^KN2/kn¹ has larval multidendritic class IV neuron | somatic clone phenotype, enhanceable by ct^UAS.cPa/Scer\GAL4^ppk.PG