1 Introduction Dbf Dbf Lyon et al., 1996; Hayes et al., 1998a Dbf + Sonic hedgehog Shh Masuya et al., 1995; Hill et al., 2003 Xt J Shh Gli3 Hui and Joyner, 1993 Dbf Indian hedgehog Ihh Yang et al., 1998 Ihh Crick et al., 2003 Shh Hayes et al., 1998b; Yang et al., 1998 Ihh Xt J Shh Hui and Joyner, 1993 − / − − / − − / − Gli3 Shh te Welscher et al., 2002 Litingtung et al., 2002 Shh Dai et al., 1999; Shin et al., 1999; Sasaki et al., 1999 Litingtung et al. (2002) Shh Patched1 Ptc1 Gritli-Linde et al., 2001 Wang et al., 2000 − / − Litingtung et al., 2002 talpid 3 Davey et al., 2006 Xt J − / − talpid 3 Dbf Hilton et al., 2005; Koziel et al., 2005 Dbf Dbf + − / − Shh Dbf Blake et al., 2003; Hayes et al., 2001 Shh Dbf Shh Dbf Ihh Dbf Shh Ihh Shh Dbf Hayes et al. (2001) Dbf Dbf Ihh Dbf Ihh Ihh Dbf Dbf Ihh 2 Results 2.1 Dbf Hand2 Gli3 Shh Shh Chiang et al., 2001; te Welscher et al., 2002 Ihh Dbf + Fig. 1 Gli3 Fig. 1 Dbf + Fig. 1 Hand2 Fig. 1 Dbf + Fig. 1 Gli3 Dbf + Fig. 1 Hand2 Fig. 1 Hand2 Dbf + Fig. 1 Hand2 Gli3 Dbf + Ihh Fig. 3 2.2 Dbf Shh Shh − / − Dbf + − / − Dbf + Fig. 2 − / − Dbf + Dbf + Fig. 2 Fig. 2 2.3 Ihh Shh Dbf + Shh Ihh Dbf + Shh Fig. 3 Riddle et al., 1993 Ihh St-Jacques et al., 1999 Dbf + Ihh Fig. 3 Ihh Shh Ihh Fig. 3 Ihh − / − Dbf + Shh Dbf + Fig. 3 Shh Dbf + Fig. 3 Ihh Dbf + Fig. 3 − / − Dbf + Ihh Fig. 3 2.4 Dbf Shh Dbf + − / − Dbf + Shh Dbf + − / − − / − Dbf + Fig. 4 Fig. 3 Ihh Ptc1 Gli1, Dbf + + Shh Gli3, Takahashi et al., 1998 + Gli3 − / − Ihh − / − Dbf + Dbf + Hand2 − / − − / − Dbf + Hand2 Fig. 1 Hayes et al., 1998b; Yang et al., 1998 Hoxd13 Dbf + − / − Dbf + Fgf8 Dbf + − / − Dbf + Fgf4 Ihh Bmp4 Dbf + − / − Dbf + Bmp4 2.5 Dbf Dai et al., 1999; Sasaki et al., 1999; Shin et al., 1999 Fig. 5 Wang et al., 2000 Fig. 5 Dbf + − / − Litingtung et al., 2002 Fig. 5 − / − Dbf + Dbf + 2.6 Dbf Ihh Dbf Ihh Dbf http://genome.ucsc.edu/ Dbf 4.5 Fig. 6 Dbf + Dbf + 4.5 Non-homologous end joining factor 1 Nhej1 Fig. 6 Nhej1 Fig. 6 Supplementary Table 2 3 2.7 IHH Dbf IHH Innis and Hedera, 2004 Dbf IHH EPHA4 Supplementary Information 3 Discussion 3.1 Ihh + Shh Ihh Dbf + Crick et al., 2003 Dbf Ihh Gli3 Hand2 Dbf + Ihh Hand2 Gli3 Dbf + Ihh + Ihh Shh Ihh Shh Gremlin Scherz et al. (2004) Shh −/− + 3.2 Dbf Dbf + − / − Dbf + Dbf + Ptc1 Gli1 Hoxd13 Hand2 Dbf + Gli3 − / − Dbf + Gli3 − / − Dbf + − / − Hoxd13 Hand2 Fgf4 Gli1 Tickle, 2006 − / − Dbf + Ihh Dbf + − / − Dbf + Gli3 Fig. 4 − / − Dbf + Fig. 5 3.3 Dbf Dbf Dbf n Alu Vassetzky et al., 2003 Dbf Nhej1 Supplementary Table 2 Dbf Ptprn Des Inha Slc4a3 Dbf Ihh de novo Nhej1 Dbf Cantagrel et al., 2007 Dbf IHH NHEJ1 IHH Dbf Ihh Dbf cis Ihh Kleinjan and van Heyningen (2005) ZRS Shh ZRS Shh Lettice et al., 2002 Dbf Ihh Dbf 4 Materials and methods 4.1 Generation and identification of mutant mice Shh Chiang et al., 1996 Dbf + Shh Chiang et al., 1996 Shh −/− Dbf + Dbf + Mus musculus castaneus Dbf D1Mit46 Ihh Mus musculus castaneus 4.2 in situ Shh +/ − Dbf + Shh +/ − Shh +/ − − / − Dbf + Shh +/ − Dbf + − / − Dbf + 2 4 2 4 in situ Wilkinson (1992) 4.3 Skeletal preparations Embryos for skeletal staining were dissected and fixed in 95% ethanol for 1–3 days. They were immersed in alcian blue stain (75% ethanol, 20% acetic acid, 3 mg/ml alcian blue) for 21–28 days at 37 °C. They were cleared in 0.8% KOH, 20% glycerol. Following clearing, they were sequentially dehydrated and stored in 50% ethanol/50% glycerol. 4.4 Western Blotting Litingtung et al., 2002 4.5 Dbf Dbf 32 Dbf Dbf Dbf Dbf Dbf Hpy Dbf Appendix A Supplementary data doi:10.1016/j.mod.2008.01.001 Appendix A Supplementary data Supplementary data