In the Trpv6 gene a loxP site was inserted into intron 12 and an FRT site flanked neomycin resistance gene cassette with a 3' loxP site was inserted downstream of the last exon (15) into intron 16 of the Ephb6 gene on the opposite strand. Subsequent flp-mediated recombination removed the neo cassette, leaving a conditional-ready allele with exons 13-15 of Trpv6 as well as exons 17 and 18 of Ephb6 floxed. (J:185996)