A cre recombinase gene and FRT-flanked neomycin resistance cassette were inserted at the translation initiation site in exon 2. Flp-mediated recombination removed the selection cassette as Col10a1tm2.1(cre)Ksec line described in J:122054. The recombination only took place in lower hypertrophic zone (HZ), which was delayed compared with that of Col10a1tm2.1(cre)Ksec line. (J:324690)