The transgene is composed of the RP23_165_D11 BAC with the cre recombinase gene inserted at the translation start site of the 210 kb Fev fragment by an FRT-flanked neomycin resistance cassette. Flp-mediated recombination removed the selection cassette. Passenger genes in the BAC include Cdk5r2, Cryba2, Ccdc108, Ihh and Nhej1. Founder FF3, FF9 (single transgene copy insertion) and FM3 were generated.