Ciona intestinalis: an emerging model for whole-genome analyses

The tadpole larvae of the ascidian Ciona intestinalis possess the most simplified chordate body plan. Analysis of the Ciona draft genome indicates that the ~153�159 Mb genome contains ~16 000 protein-coding genes. Among these is a fundamental set of conserved chordate proteins involved in cell signaling and development. A thorough examination of Ciona gene expression (the transcriptome) is ongoing, including large-scale expressed sequence tag analyses, cDNA sequencing and in situ hybridization screens. Together with recent advances in the methodology used to investigate gene regulation and function, these make Ciona an attractive experimental system for genome level analysis of chordate developmental genetics.