Figure 5From: How Hox genes can shed light on the place of echinoderms among the deuterostomesExpression pattern of the Intervening Zone and of related genes among bilaterian Animalia. The IZ (separating Otx and Hox1 domains) corresponds to the midbrain-hindbrain boundary (MHB) in vertebrates, the neck region of urochordates, the anterior part of the second somite in cephalochordates, the deutocerebrum of insects, and to the anterior part of the trunk in annelids. Expression domains of Pax2/5/8 and En are shown (diamonds) only when they are located between those of Otx and Hox1. Expression domains of Pax2/5/8 are still largely unknown in Ambulacraria, hence the two alternative hypotheses shown for this character.Back to article page