Eggs laid by females containing large homozygous follicle cell clones lack dorsoventral eggshell polarity. The region surrounding the micropyle is reduced in size and lacks follicle cell imprints.
Med13 mutant clones display defects in dorsal cluster neurons but do not exhibit remodeling defects in γ mushroom body neurons.
Lethal in trans with Med12, Med11, Med14, Med16, Med18 or Df(3R)E40. Med13/Med15 flies lack the posterior crossvein and have a large discontinuity in wing vein L4. Females containing homozygous Med13 germ line clones mated to Med14/+ males produce eggs of two phenotypic classes: 48% have a partially ventralised phenotype (presumptive zygotic genotype Med13/+) characterised by the presence of dorsal hairs, internalisation of filzkorper and elimination of dorsolaterally derived structures of the head. The second class of embryos (presumptive zygotic genotype Med13/Med14) do not differentiate any dorsal structures, but instead differentiate ventral denticle bands around the entire embryonic circumference. These embryos do not differentiate amnioserosa.