Cartoon showing the expression of Slits (red) and Robo receptors (blue) during trunk neural crest development. A Represents a pre-migratory neural crest cells that simultaneously expresses Slit and its Robo receptors, these cells are not motile. B Represents a migrating neural crest cells that expresses Robo receptors but no Slit, these are highly motile cells avoiding dermomyotome (Jia et al., 2005). C Represents neural crest cells expressing Robo receptors stopping by the dorsal aorta after encountering Slit molecules expressed at the entrance of the developing gut, these cells are non-motile, non-epithelial (De Bellard et al., 2003).