0Chordates and echinoderms shared a key characteristic of animal taxonomy- that of embryo growth pattern. These two groups comprise the deuterostomes whose embryological development differs greatly from the protostomes ( molluscs, annelids and arthropods). These embryological development patterns are guided by genetic differences in the expression of Hox genes, which suggests that echinoderms and chordates share a key characteristic very distinct from other animal groups. And, although the adult echinoderms look different from the chordates, an early stage in their development looks more closely related to the chordates.
