MBE Advance Access published online on May 4, 2007
Molecular Biology and Evolution, doi:10.1093/molbev/msm086
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Research Article |
Mitochondrial Genome and Nuclear Sequence Data Support Myzostomida as Part of the Annelid Radiation
1 Unit of Evolutionary Biology/Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Haus 26, D-14476 Potsdam-Golm, Germany
2 Marine Biology Laboratory, Natural Sciences Building, University of Mons-Hainaut, Av. Champs de Mars 6, B-7000 Mons, Belgium
3 Animal Systematics and Evolution, Institute for Biology, Zoology, Free University Berlin, Koenigin-Luise-Str. 1-3, D-14195 Berlin, Germany
4 Department of Biology, Colgate University, Hamilton, NY 13346, USA
5 Department of Biological Sciences, Auburn University, 101 Life Science Building, AL 36849, USA
6 Free University of Brussels, Institute of Molecular Biology and Medicine, Laboratory of Evolutionary Genetics, Cp 300, Rue Jeener and Brachet 12, B-6041 Gosselies, Belgium
Corresponding author: Christoph Bleidorn, Unit of Evolutionary Biology/Systematic Zoology, Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, Haus 26, D-14476 Potsdam-Golm, Germany. phone: 00493319775604, fax:00493319775070, email: Bleidorn{at}uni-potsdam.de
Received for publication January 22, 2007. Revision received April 17, 2007. Accepted for publication April 25, 2007.
The echinoderm symbionts Myzostomida are marine worms that show an enigmatic lophotrochozoan body plan. Historically, their phylogenetic origins were obscured due to disagreement about which morphological features are evolutionarily conserved, but now most morphological evidence points to annelid origins. In contrast, recent phylogenetic analyses using different molecular markers produced variable results regarding the position of myzostomids, but all suggested these worms are not derived annelids. To re-examine this issue, we analyzed data from nuclear genes (18S rDNA, 28S rDNA, Myosin II, and Elongation Factor-1
), and a nearly complete myzostomid mitochondrial genome. Here, we show that the molecular data are in agreement with the morphological evidence that myzostomids are part of the annelid radiation. This result is robustly supported by mitochondrial (gene order and sequence data) and nuclear data, as well as by recent ultrastructural investigations. Using Bayes factor comparison, alternative hypotheses are shown to lack support. Thus, myzostomids probably evolved from a segmented ancestor and gained a derived anatomy during their long evolutionary history as echinoderm symbionts.
Key Words: Myzostomida • Annelida • Myosin II • mitochondrial genome • gene order • long branch attraction
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  R. A Jenner and D.T. J Littlewood Problematica old and new Phil Trans R Soc B, April 27, 2008; 363(1496): 1503 - 1512. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Giribet Assembling the lophotrochozoan (=spiralian) tree of life Phil Trans R Soc B, April 27, 2008; 363(1496): 1513 - 1522. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. H. Struck and F. Fisse Phylogenetic Position of Nemertea Derived from Phylogenomic Data Mol. Biol. Evol., April 1, 2008; 25(4): 728 - 736. [Abstract] [Full Text] [PDF]
|
|