Fig. 4. Gut phenotypes of Pitx2 allelic combinations. (A-E) Gut looping in 10.5 dpc embryos visualized using the probe for sonic hedgehog. Genotypes are shown. (F-J) Duodenal rotation in 12.5 dpc embryos visualized using the probe for sonic hedgehog. Genotypes are shown. Direction of duodenal rotation is outlined. (K-M) Pitx2c expression in duodenum shown by whole-mount in situ hybridization. Note bilateral expression as denoted by the arrows. (N,O) Normal and arrested midgut rotation in wild-type (N) and 
ab;ab mutant (O) embryos. Direction of midgut looping is outlined. Annular pancreas in ab;ab mutant embryo (O) is denoted by arrows.
