In terms of evolution, sea urchins are in an interesting position between vertebrates and invertebrates. "The sea urchin fills a large evolutionary gap in sequenced genomes," said George Weinstock, Ph.D., co-director of the sea urchin sequencing project. Being more closely related to humans than other invertebrates such as flies and worms, "it allows us to see what went on in evolution after the split between the ancestors that gave rise to humans and insects. The sea urchin genome provided plenty of unexpected rewards and was a great choice for sequencing."
In the 1990s, sea urchins became a valuable fishery in Maine, but their stocks were quickly depleted. Linda Mercer, Director of the Bureau of Resource Management at Maine's Department of Marine Research, welcomed the news of the project's completion: "We are certainly interested in reestablishing the sea urchin population along the Maine coast, and any research that can continue to improve our understanding of sea urchin biology would be helpful."
The DNA that was sequenced came from a male California purple sea urchin, not one of the green sea urchins that live in Maine waters. Purple urchins are found along the west coast from Baja to Alaska, whereas the green ones, close relatives of the purple, are found in cold Northern waters on both the east and west coasts.
All sea urchins, however, have round shells covered with spines. Like the other members of the phylum Echinodermata, which includes starfish and sea cucumbers, they have fivefold symmetry and move by means of hundreds of tiny, adhesive "tube feet." They eat algae with a mouth surrounded by five teeth on the bottom of their shell and excrete through a hole at the top.
The sea urchin has long had a strong
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Contact: Jerilyn Bowers
jeri@mdibl.org
207-288-3147
Mount Desert Island Biological Laboratory
9-Nov-2006