- Rokhsar, D.S.;
- Chapman, J.;
- Putnam, N.;
- Dehal, P.S.;
- Rash, S.;
- Gelpke-Sollweijn, M.;
- Terry, A.;
- Zhou, C.;
- Zhang, Q.;
- Goodstein, D.L.;
- Kobayashi, A.;
- Keys, D.;
- DiGregorio, A.;
- Medina, M.;
- Boore, J.L.;
- Doggett, N.;
- Detter, C.;
- Richardson, P.M.;
- Lucas, S.;
- Satou, Y.;
- Kohara, Y.;
- Satoh, N.;
- Levine, M.;
- Hawkins, T.L.
The first chordates appeared over a half a billion years ago, providing the ancestral stock from which modern vertebrates emerged. To shed some light on the chordate origins, we have sequenced the genome of Ciona intestinalis, a sea squirt whose lineage split from that of vertebrates in the mid Cambrian. Ciona has long been a popular model system for the study of development, featuring world-wide and year-round availability, easily visualized cells and morphogenetic processes, simple methods for transient transgene expression, and a growing genomic infrastructure including extensive EST and cDNA collections. A comparison of the assembled Ciona genome sequence and gene complement with available invertebrate and vertebrate sequences provides insight into the origins and development of a chordate and vertebrate systems including the nervous systems, muscular, immune and endocrine systems, as well as the evolution of the chordate body plan. The Ciona genome provides a foundation for a genome-scale analyses of regulatory networks through chordate development.