A TI{CRIMIC.TG4.2} DNA cassette has been inserted into stg1, in a coding intron, and is predicted to gene trap all annotated transcripts of the gene. The insertion is also within CG15446, not in a coding intron, and is not predicted to gene trap this gene. The TI{CRIMIC.TG4.2} cassette was inserted using the CRISPR/Cas9 technique together with a donor plasmid to drive homology directed repair. The sgRNA sequence used to target the gene was: GGTGACGGCCCATTACCATTGGG. The homology arms of the donor plasmid used were designed such that there is a small gap between the 3' end of the 5' arm and the 5' end of the 3' arm, thus the insertion of the TI{CRIMIC.TG4.2} cassette is predicted to be accompanied by a deletion of 23bp of genomic sequence flanking the insertion site. The PCR check of the insertion gave the expected sized product for the right flank, but no product for the left flank.