Fig. 2. Transgenic An. stephensi mosquitoes expressing the dsRED marker. (A) Fluorescence photomicrographs of transgenic fourth instar larva, viewed from the ventral side. Top, dsRED fluorescence alone; bottom, fluorescence superimposed on a light micrograph. dsRED expression is regulated by the 3xP3 promoter, which is active in the eyes and nervous system. (B) Fluorescence photomicrographs of an adult head viewed from the ventral side (left, fluorescence only; right, merged fluorescence and light micrograph). Note that all ommatidia express the dsRED marker, but because fluorescence depends on the angle of the incident (activating) light, only a few are visible in the photo.