A targeting construct consisting of CMV enhancer sequence, a beta actin promoter, a floxed beta-geo stop cassette, loxN, Kozak-bovine tau/mTurquoise-WPRE-pA, lox2272, loxN, Kozak-bovine tau/tdTomato-IRES-dominant-negative rat Gnas mutant-WPRE-pA, lox2272 was inserted via homologous recombination. The allele allows stochastic Cre/lox recombination for functional mosaic analysis utilizing two distinct subpopulation after cre mediated recombination. (J:310193)