Pontes-Quero, S. et al. Cell 170, 800–814.e18 (2017).

Mosaic genetic analyses are widely used in Drosophila to study gene function in a cell-autonomous or tissue-specific fashion. Such analyses are less easily conducted in mice. Pontes-Quero et al. report tools to generate mosaic mice efficiently and relatively quickly. Their inducible, fluorescent, and functional genetic mosaic (ifgMosaic) strategy is inspired by the Brainbow technology and relies on the mutually exclusive expression of three sets of fluorescent reporters and genes of interest from a single construct. The construct is available with either membrane-bound or nucleus-targeted fluorescent reporters. When combining the two constructs in the same mouse, in principle up to six genes can be studied in up to 15 distinct clonal combinations. To facilitate generation of the mosaic mice, the researchers report efficient cloning and transgenesis strategies. The ifgMosaic approach is applied to study the Notch and VEGF pathways during neurogenesis and angiogenesis.