Sequencing the genome of the hemichordate Saccoglossus kowalevskii

Hemichordates are the phylum of bilateral animals most closely related to chordates, the phylum that includes vertebrates such as human. The hemichordate is a three-part worm-like animal, but possesses many chordate-like traits long thought to hold insights into chordate evolution. These traits include gill slits (1), a post-anal tail-like extension (2), a notochord-like stomocord (3), a neurulated portion of the nervous system, a podocyte-containing kidney (3), possibly a pituitary-like proboscis pore (4), and possibly an endostyle-like pharyngeal region with homology to the thyroid (5). In addition, recent in situ hybridization studies have revealed extensive hemichordate–chordate similarities in the expression domains of 22 neural patterning genes (6). We propose the generation of a 6X assembly of the hemichordate Saccoglossus kowalevskii (the acorn worm) genome to advance hemichordate–chordate comparisons and to illuminate chordate origins. The S. kowalevskii genome sequence will also accelerate work on the development and organization of members of the hemichordate phylum. In Section A of this White Paper, we discuss the specific biological advances anticipated from the availability of a hemichordate genome by highlighting its potential contribution to informing human biology, informing the human sequence, providing a better connection between the sequences of non