A set of third chromosome mutant stocks derived by insertional mutagenesis using the P-element construct P{lacW}; most lines have a lethal or semi-lethal phenotype. The P{lacW} construct carries a w+mC mini-white visible marker, Ecol\lacZ enhancer trap sequences, and bacterial sequences that allow plasmid rescue (FBrf0049800).
The orientation of the insertion was not reported. P{lacW} in the first exon of the trio transcript, in the untranslated region. P{lacW}trioS137203 and P{lacW}trioS138606 map within 5bp of each other.