Learn More
The first chordates appear in the fossil record at the time of the Cambrian explosion, nearly 550 million years ago. The modern ascidian tadpole represents a plausible approximation to these ancestral chordates. To illuminate the origins of chordate and vertebrates, we generated a draft of the protein-coding portion of the genome of the most studied(More)
Lancelets ('amphioxus') are the modern survivors of an ancient chordate lineage, with a fossil record dating back to the Cambrian period. Here we describe the structure and gene content of the highly polymorphic approximately 520-megabase genome of the Florida lancelet Branchiostoma floridae, and analyse it in the context of chordate evolution. Whole-genome(More)
Ascidians and vertebrates belong to the Phylum Chordata and both have dorsal tubular central nervous systems. The structure of the ascidian neural tube is extremely simple, containing less than 400 cells, among which less than 100 cells are neurons. Recent studies suggest that, despite its simple organization, the mechanisms patterning the ascidian neural(More)
The Pax6 gene plays a developmental role in various metazoans as the master regulatory gene for eye patterning. Pax6 is also spatially regulated in particular regions of the neural tube. Because the amphioxus has no neuromeres, an understanding of Pax6 expression in the agnathans is crucial for an insight into the origin of neuromerism in the vertebrates.(More)
BACKGROUND Dinoflagellates are known for their capacity to form harmful blooms (e.g., "red tides") and as symbiotic, photosynthetic partners for corals. These unicellular eukaryotes have permanently condensed, liquid-crystalline chromosomes and immense nuclear genome sizes, often several times the size of the human genome. Here we describe the first draft(More)
Despite the enormous ecological and economic importance of coral reefs, the keystone organisms in their establishment, the scleractinian corals, increasingly face a range of anthropogenic challenges including ocean acidification and seawater temperature rise. To understand better the molecular mechanisms underlying coral biology, here we decoded the(More)
The smallest reported bacterial genome belongs to Tremblaya princeps, a symbiont of Planococcus citri mealybugs (PCIT). Tremblaya PCIT not only has a 139 kb genome, but possesses its own bacterial endosymbiont, Moranella endobia. Genome and transcriptome sequencing, including genome sequencing from a Tremblaya lineage lacking intracellular bacteria, reveals(More)
The origin and elaboration of the central nervous system played an important role in chordate and vertebrate history. All chordates possess a dorsal tubular central nervous system, but elaboration of dorsoventral and segmental pattern is far more pronounced in cephalochordates and vertebrates than in the more basal urochordates. Analysis of the(More)
The ascidian tadpole represents the most simplified chordate body plan. It contains a notochord composed of just 40 cells, but as in vertebrates Brachyury is essential for notochord differentiation. Here, we show that the misexpression of the Brachyury gene (Ci-Bra) of Ciona intestinalis is sufficient to transform endoderm into notochord. Subtractive(More)
Ciona is an emerging model system for elucidating gene networks in development. Comprehensive in situ hybridization assays have identified 76 regulatory genes with localized expression patterns in the early embryo, at the time when naïve blastomeres are determined to follow specific cell fates. Systematic gene disruption assays provided more than 3000(More)