Fig. 5. Changing Yellow and Ebony expression is sufficient to alter pigment patterns. (A) Ectopic expression of Yellow results in a subtle increase of black pigment in the thorax relative to wild type. (B) In the abdomen, this expression causes a slight widening of the pigment stripe (arrowhead indicates the border between wild-type and ectopic pigmentation), as well as the dorsal midline pigment (arrow). (C) Ectopic expression of Ebony in the same cells results in a tanning of the thorax and a removal of melanin in the abdominal stripe (D). (E) In ebony¹ mutants, ectopic expression of Yellow induces black pigment in the thorax (arrow) and the abdomen (F). (G,H) Co-expression of Yellow and Ebony results in a phenotype more similar to wild type than does ectopic expression of either protein alone. (B,D,F,H) Brackets indicate the approximate boundaries of pannier-Gal4 expression.