The M{iwhiteΔ9} construct contains 'iwhiteΔ9', a copy of the w gene that is non-functional due to 5' and 3' truncations that remove the promoter, 5' UTR, start codon, the last 30 amino acids, and the 3' UTR, and that also contains a 9bp in-frame deletion in the coding sequence that removes a SacI site. M{iwhiteΔ9} acts as a donor template in an assay to measure interhomolog homologous recombination (HR), when used with the M{Sce.white} repair target construct. A y+t* marker is also present upstream of the 'iwhiteΔ9' sequence. Expression of I-SceI can induce a DSB at the RS(I-SceI) site in M{Sce.white}, and gene conversion of the 'Sce.white' sequence using a M{iwhiteΔ9} donor template at the same allelic locus on the homologous chromosome can can produce a functional w gene containing the 9bp deletion from the 'iwhiteΔ9' donor template, resulting in progeny with orange eyes.
