Fig. 5. Comparison of ventral patterning defects in Nkx2.1^–/–, Gsh2^–/– and Shh^–/– single mutants, and Nkx2.1^–/–;Gsh2^–/– double mutants. At E12.5, Nkx2.1^–/–;Gsh2^–/– double-mutant mice (D,I,N,S) display a notable decrease in the size of ventral telencephalic structures and a reduction in the expression of Dlx2, Mash1, Gsh1 and Lhx6 compared with controls (A,F,K,P). Comparison with single Gsh2^–/– mutants (B,G,L,Q) and single Nkx2.1^–/– mutants (C,H,M,R) is also shown. Arrows (A-N) show the dorsal limits of Dlx2, Mash1 and Gsh1 gene expression. In less severely affected Shh^–/– mutants, expression of Dlx2 and Mash1 (arrows) persists in the ventral telencephalon (E,J). By contrast, expression of Gsh1 and Lhx6 is never detected in these animals (O,T). Scale bar in A: 200 µm for A-D,F-I,K-N,P-S; 275 µm for E,J,O,T.