Summary of the expression pattern of dental markers during early tooth development.

Results from this study (a), were juxtaposed to information available from: Ablooglu et al, 2007 [14], (b); Jackman et al, 2004 [15], (c); and Borday-Birraux et al.,2006 [12], (d). 4V1 is the first tooth formed. The development of 4V1 is closely followed by the formation of neighbouring teeth. The development of 3V1 on the medial side of 4V1 slightly precedes the formation of 5V1 on the lateral side of 4V1. The expression pattern of dlx2a, dlx2b, connexin 43 and osterix does not clarify the identity of ext2−/− tooth. However, comparison of the expression patterns in ext2−/− and slc35b2−/− indicate loss of 5V1 in both mutants. Week expression is indicated by brackets; -, gene expression was not detected; na, not analysed.