Roles of retinoic acid and Tbx1/10 in pharyngeal segmentation: amphioxus and the ancestral chordate condition

Abstract

These results indicate that the involvement of RA signaling and its interactions with Tbx1/10 in head segmentation preceded the evolution of neural crest and were thus likely present in the ancestral chordate. Furthermore, developmental comparisons between different deuterostome models suggest that the genetic mechanisms for pharyngeal segmentation are evolutionary ancient and very likely predate the origin of chordates.