Homozygous lethal deletion chromosome balanced by GFP-marked translocation. Heterozygotes are WT with pharyngeal GFP signal, and segregate WT GFP, arrested nT1[qIs51] aneuploids, and non-GFP gk526 homozygotes (variable arrest, early larval). Homozygous nT1[qIs51] inviable. Pick WT GFP and check for correct segregation of progeny to maintain.