Skip Navigation



MBE Advance Access published online on November 9, 2005
Molecular Biology and Evolution, doi:10.1093/molbev/msj055
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow Supplementary Material
Right arrow All Versions of this Article:
23/3/541    most recent
msj055v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Rychel, A. L.
Right arrow Articles by Swalla, B. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Rychel, A. L.
Right arrow Articles by Swalla, B. J.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2005. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org
Accepted November 2, 2005

Research Article

Evolution and Development of the Chordates: Collagen and Pharyngeal Cartilage

Amanda L. Rychel 1, Shannon E. Smith 2, Heather T. Shimamoto 2, and Billie J. Swalla 1*

1 Center for Developmental Biology and Biology Department, University of Washington, Seattle, WA 98195-1800; Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250-9299
2 Center for Developmental Biology and Biology Department, University of Washington, Seattle, WA 98195-1800

* To whom correspondence should be addressed.
Billie J. Swalla, E-mail: bjswalla{at}u.washington.edu


  Abstract

Chordates evolved a unique body plan within deuterostomes and are considered to share five morphological characters, a muscular, post-anal tail, a notochord, a dorsal neural tube, an endostyle and pharyngeal gill slits. The phylum Chordata typically includes three sub-phyla, Cephalochordata, Vertebrata, and Tunicata, the latter showing a chordate body plan only as a larva. Hemichordates, in contrast, have pharyngeal gill slits, an endostyle and a post-anal tail, but appear to lack a notochord and dorsal neural tube. Since hemichordates are the sister group of echinoderms, then morphological features shared with the chordates must have been present in the deuterostome ancestor. No extant echinoderms share any of the chordate features, so presumably they have lost these structures evolutionarily. We review the development of chordate characters in hemichordates and present new data characterizing the pharyngeal gill slits, and their cartilaginous gill bars. We show that hemichordate gill bars contain collagen and proteoglycans, but are acellular. Hemichordates and cephalochordates, or lancelets, show strong similarities in their gill bars, suggesting an acellular cartilage may have preceded cellular cartilage in deuterostomes. Our evidence suggests the deuterostome ancestor was a benthic worm with gill slits and acellular gill cartilages.

Keywords: evolution and development; chordate evolution; tunicates; cephalochordates; hemichordates; cartilage; collagen.
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
J.-Y. Exposito, C. Larroux, C. Cluzel, U. Valcourt, C. Lethias, and B. M. Degnan
Demosponge and Sea Anemone Fibrillar Collagen Diversity Reveals the Early Emergence of A/C Clades and the Maintenance of the Modular Structure of Type V/XI Collagens from Sponge to Human
J. Biol. Chem., October 17, 2008; 283(42): 28226 - 28235.
[Abstract] [Full Text] [PDF]

Home page
 Biol. Bull.Home page
R. M. Freeman JR., M. Wu, M-M. Cordonnier-Pratt, L. H. Pratt, C. E. Gruber, M. Smith, E. S. Lander, N. Stange-Thomann, C. J. Lowe, J. Gerhart, et al.
cDNA Sequences for Transcription Factors and Signaling Proteins of the Hemichordate Saccoglossus kowalevskii: Efficacy of the Expressed Sequence Tag (EST) Approach for Evolutionary and Developmental Studies of a New Organism
Biol. Bull., June 1, 2008; 214(3): 284 - 302.
[Abstract] [Full Text] [PDF]

Home page
 Phil Trans R Soc BHome page
C. J Lowe
Molecular genetic insights into deuterostome evolution from the direct-developing hemichordate Saccoglossus kowalevskii
Phil Trans R Soc B, April 27, 2008; 363(1496): 1569 - 1578.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
G. Zhang and M. J. Cohn
Hagfish and lancelet fibrillar collagens reveal that type II collagen-based cartilage evolved in stem vertebrates
PNAS, November 7, 2006; 103(45): 16829 - 16833.
[Abstract] [Full Text] [PDF]

Home page
 Integr. Comp. Biol.Home page
L. Zeng, M. W. Jacobs, and B. J. Swalla
Coloniality has evolved once in Stolidobranch Ascidians
Integr. Comp. Biol., June 1, 2006; 46(3): 255 - 268.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.