A loxP recognition sequence for the Cre site-specific recombinase was inserted into the Taar2 gene using a targeting vector with homology arms flanking a puromycin selection (puro) cassette and a second loxP sequence was inserted into the Taar9 gene using a neomycin (Neo) selection cassette. Cre recombination was used to delete the intervening 170 kb of the mouse chromosome 10. (J:337644)