Fig. 1. Dysmorphologies in rs mutants. (A) A typical rs/rs animal with the original BALB/c background and (B) rs/rs and rs/+ animals with BALB/c-C57BL/6 mixed backgrounds. (C-F) Vertebrae from newborn rs/rs viewed from the ventral (C), dorsal (D,E), or right-lateral (F) sides. (G,H) Alcian Blue-stained E14 skeletons (dorsal view) from control (G) and rs/rs (H) show vertebral segmentation defects. Note neural arch fusion (black arrowheads in H) and its loss (yellow arrowheads in H). (I,J) SEM of control (I) and rs/rs (J) embryos at E11 shows neural tube closure defects in the lumbo-sacral region (the arrowhead in J). (K) Oligodactyly (arrowhead) is occasionally observed in rs/rs. Scale bars: 100 µm.