Expression of Spry2 in somites and limb buds is closely associated with MyoD . (A) Whole mount in situ hybridisation of chick embryo at HH23 showing Spry2 expression in limb buds and somites, with strong signal visible in the hypaxial domains (arrowheads). (Ai) Transverse section of embryo in (A) at the level of trunk somite showing Spry2 expression throughout the myotome with high levels in the hypaxial domain (arrowheads). (Aii) Frontal section shows Spry2 expression in the myotomes, anterior and posterior myotome edges are indicated by arrowheads. (B-Bii) Double in situ hybridisation detects Spry2 (purple, NBT/BCIP) and MyoD (red, Fast red) at HH24, (B) whole mount chick embryo shows overlap in somites and limb bud, (Bi) transverse and (Bii) frontal sections show overlapping expression of Spry2 and MyoD. Magnifications: 20x in (A), 200x in (Ai), 400x in (Aii & Bii), 22x in (B), 100x in (Bi).