Wheaton scientists decode sea urchin genome, publish in Science

NORTON, Mass. -- Wheaton faculty and students, members of the Sea Urchin Genome Sequencing Project Consortium that is led by the Human Genome Sequencing Center at Baylor College of Medicine in Houston, are among the scientists who announced today the decoding and analysis of the genome sequence of the sea urchin, Strongylocentrotus purpuratus.

The genome of a male California purple sea urchin was sequenced, and contained over 814 million letters, spelling out 23,300 genes. Nearly 10,000 of the genes were scrutinized by the international consortium of 240 scientists from over 70 institutions in 11 countries. The high quality ''draft'' sequence covers over 90 percent of the genome. The primary results are presented in the November 10 issue of Science, and a companion manuscript authored by Wheaton scientists is contained in a special issue of Developmental Biology appearing on December 1, 2006.

Biology Professor Robert Morris led the 30-plus member Wheaton team, which included paper co-authors Shawn McCafferty, assistant professor of biology; Jonah Cool '04 (Palo Alto, Calif.); Erin Allgood '07 (Bennington, N.H.); Ashlan Musante '08 (Shelton, Conn.); Kyle Judkins '08 (Scarborough, Maine); Blair Rossetti '09 (Plymouth, Mass.); and Amanda Rawson '09 (Dudley, Mass.). The team's all-night sequencing ''parties'' during the 2005-06 academic year provided the data for analysis.

''This is a very exciting moment for Wheaton, for my lab, and for my collaborators,'' Morris said. ''I never thought I'd get a Science paper, let alone Science and Developmental Biology papers in one year. The fact that six Wheaton students contributed enough research effort to be co-authors is a great credit to them and to the natural sciences at Wheaton.''

Rossetti, a biochemistry major and mathematics minor, assembled kinesin genes--motor proteins that function in moving vesicles, organelles and molecules along the microtubules of the cell--from sea urchin genome data. He said that although the publication is exciting, it doesn't beat the experience of working in Morris' lab.

''Being a part of this project has given me insight into the inner workings of the larger scientific community,'' Rossetti explained. ''Not until I began the research did I know the amount of work put into a paper of this magnitude. The publication and time spent as a part of the Morris Lab has opened doors to new and exciting opportunities for the future.''

Musante, a chemistry major and biology minor who plans to pursue a Ph.D. in chemical biology or biochemistry, has worked in the Morris lab for more than a year and regularly attended his SUGAR (Sea Urchin Genome Annotation Research) parties.

''The data from this project will be invaluable to biologists for years to come, and I am thrilled to have been a part of collecting and analyzing it,'' she said. ''Being published in scientific journals as prestigious as Science and Developmental Biology as an undergraduate is really a reflection of Prof. Morris' willingness to completely involve his students in meaningful research projects. Graduate students often work for years on projects to get a publication, and we have gotten two from this one project!''

There was great interest among international scientists in the sea urchin as a target for genome sequencing because these animals share a common ancestor with humans. That ancestor lived over 540 million years ago and gave rise to the Deuterostomes, the superphylum of animals that includes phyla such as echinoderms and chordates, the phylum to which humans and other vertebrates belong.

The comparison of the genes of the sea urchin to the human gene list shows which human genes are likely to be recent innovations in human evolution and which are ancient. It also shows which human genes have changed slowly in the lineage from the ancestral Deuterostome animal and which genes are evolving rapidly in response to natural selection. This will make it possible one day to know the history of every human gene - and build a picture of what the extinct ancestors that gave rise to animal life from worms to humans looked like.

Because of its evolutionary position, the sea urchin genome-one of the most challenging to sequence to date-was a sample of unknown biological territory. Some of the notable surprises and discoveries were:

• The sea urchin had most of the same gene families found in man.

• The sea urchin has some of the genes of the acquired immunity system, but its innate immunity branch is greatly expanded with ten- to twenty-times as many genes as in humans.

• The sea urchin has genes for sensory proteins that are involved in vision and hearing in man.

Sea urchin photo © Charles Hollahan