Figure 2.

Testing of Mod(mdg4) variants for insulator function in y² ct⁶ male flies. Schematics show the structure of the (A) y² and (B) ct⁶ or ct^k alleles; beginnings and direction of the yellow and cut genes are shown by arrows; ovals denote wing (w), body (b), bristle (br) and wing margin (wm) enhancers (En); triangles show insertions of gypsy with flanking long terminal repeats and the Su(Hw) insulator as a black (semi)circle. Photographs collate (A) the body cuticle (bottom-right, bristle pigmentation: 5 for wild type, 1 for none) and (B) the wing phenotypes; ModWT and ModΔQ refer to transgenic expression of the variant specified in Fig 1A; mod(mdg4)^T6 itself produces ModΔC; mod(mdg4)^u1 is the null mutation. Mod(mdg4), Modifier of mdg4; Su(Hw), Suppressor of Hairy wing; y², yellow mutation associated with gypsy insertion.