Genomic analysis of immunity in a Urochordate
and the emergence of the verterate immune system: "waiting for Godot".
Migratory neural crest-like cells form body pigmentation in a urochordate
Developmental expression of Pax1/9 genes in urochordate
and hemichordate gills: insight into function and evolution of the pharyngeal epithelium.
According to recent molecular phylogenies, urochordates
are the sister group to the vertebrates (Delsuc et al.
have become popular model organisms in the effort to deduce information about the common chordate ancestor.
It is present in urochordates
, cephalochordates, and larval lampreys, and its function is secretion of a mucous net to retain particles during feeding (Olsson, 1965; Deibel and Powell, 1987; Hiruta et al.
ascidians [2, 12]), others have found no significant relationship in urochordates
or echinoderms (14) (although the number of replicates was low in both groups).
with muscular locomotion provide a fifth independent divergence in locomotory structure.
, hemichordates, and echinoderms); but complete genome sequences have not yet been obtained for species representative of these phyla.
This idea is consistent with the absence of gill skeletal structures in adult pterobranchs, the adult enteropneust Protoglossus, urochordates
, and developmental stages of all other chordates.
Most transparent urochordates
are found in the exclusively pelagic Thaliacea, which comprises the pyrosomids, salps, and doliolids (Godeaux et al.
Regardless of whether ancestral tunicates more closely resembled the adult than its larva [3, 4], or vice versa , urochordates
form a sister group to chordates (e.