Subject: l(1)G0169 identity We have performed complementation tests with the l(1)G0169 gene (Bloomington stock P-1874) and discovered that it is an allele of l(1)10Bb. The P-1874 stock fails to complement l(1)10Bb1 but the double mutant can be rescued by l(1)10Bb+ P element transgenes. The P insertion was originally reported to map at 10B1-2 whereas l(1)10Bb mapped to 10B4-5 (where it belongs); however, the sequencing project moved l(1)10Bb to 10B11. The reported yolk nuclear (vitellophage) staining of this enhancer trap is likely due to its proximity to the vitellophage-specific enhancer of the adjacent sisA gene. We do not have any molecular data on the insertion site. Jim Erickson James W. Erickson Assistant Professor Department of Biological Sciences Columbia University 600 Fairchild 1212 Amsterdam Ave Mail Code 2402 New York, NY 10027