The recent genome sequencing of a non‐vertebrate deuterostome, the ascidian tunicate Ciona intestinalis, makes a substantial contribution to the fields of evolutionary and developmental biology.1 Tunicates have some of the smallest bilaterian genomes, embryos with relatively few cells, fixed lineages and early determination of cell fates. Initial analyses of the C. intestinalis genome indicate that it has been evolving rapidly. Comparisons with other bilaterians show that C. intestinalis has lost a number of genes, and that many genes linked together in (...) most other bilaterians have become uncoupled. In addition, a number of independent, lineage‐specific gene duplications have been detected. These new results, although interesting in themselves, will take on a deeper significance once the genomes of additional invertebrate deuterostomes (e.g. echinoderms, hemichordates and amphioxus) have been sequenced. With such a broadened database, comparative genomics can begin to ask pointed questions about the relationship between the evolution of genomes and the evolution of body plans. BioEssays 25:529–532, 2003. © 2003 Wiley Periodicals, Inc. (shrink)

The role of Brachyury and other T-box genes in the differentiation of mesoderm and endoderm of vertebrates is well established. Recently, homologues of Brachyury have been isolated from an increasing number of diverse organisms ranging from Cnidaria to vertebrates and insects. Comparative expression and function analysis allows the origin of the mesoderm and the evolution of the developmental role of Brachyury gene family in metazoans to be traced. The data suggest that an ancestral function of Brachyury was to designate a (...) blastoporal region that had distinct properties in induction and axis elongation. A subset of blastoporal cells expressing Brachyury and other genes that convey specific mesodermal functions may have segregated as a distinct cell population from this region in the course of mesoderm evolution. BioEssays 23:788–794, 2001. © 2001 John Wiley & Sons, Inc. (shrink)