Fig. 2. Restricted expression of Tbx20 isoform a. (A) cDNAs encoding Tbx20 isoforms a-d [adapted, with permission, from Stennard et al. (Stennard et al., 2003)]. Location and size of the in situ probes are indicated, along with nucleotide positions along Tbx20 cDNA. (B) In situ hybridization using Tbx20 (left) or Tbx20a (right) in situ probes on E9.5, E11.0 and E12.0 embryos. Apparent Tbx20a staining in brain at E9.5 is due to artefactual probe trapping. lv, left ventricle; rv, right ventricle; ot, outflow tract.