Gypsy insulators converted into the endogenous yellow gene. (A) A map of the yellow gene. The coding region is represented by black rectangles, untranslated regions are represented by open rectangles, and enhancers are represented by shaded ovals. Enhancers are wing (W), body (B), bristle (Br), and tarsal claw (TC). The gypsy insulators (filled triangles) were inserted at positions -900, -700, -300, and +660 relative to the start site of transcription (bent arrow). Restriction sites are SalI (S), HinD III (H), BglII (G), and KpnI (K). (B) The level of yellow expression in the ygin lines is indicated for the wing, body, bristle, and tarsal claw tissues and was inferred by analyses of cuticle phenotype. (C) Southern blot analysis of the y+660gin genomic DNA digested with KpnI and probed with a SalIto BglII fragment of yellow that includes the entire gene. The first lane is CS, and the remaining lanes are three independent y+660gin lines. Sizes in kilobases are indicated on the left, with arrows on the right showing the sizes of hybridizing bands.