Zhou, W. et al. PLoS One 7, e31997 (2012).

To modify the fly genome, several rounds of genetic crosses are often required. Mutant progeny can be identified using the white gene, which produces flies with red eye color over a background of their siblings with white eye color. Visually inspecting the eyes of hundreds of flies can be time-consuming, however, particularly when the efficiency of the genetic modification is low and mutants are rare. Zhou et al. generated a dual genetic marker that can aid in this selection process. The group uses a white::Neo gene encoding a chimeric protein that confers resistance to neomycin as well as red eye color. The authors used white::Neo to screen for several fly mutants showing that the dual selection marker enriched the frequency of the targeting mutants by up to fifty times. The antibiotic can be fed to fly larvae, simplifying the mutant selection process.