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Sea Urchin Genome
Scientists have uncovered the purple sea urchin's 23,300 genes. (Photo by Charles Hollahan)
The sea urchin is a favorite animal model among developmental biologists, just like the fruit fly and the worm. But it has one advantage over its fellow invertebrates: its genome is closer to that of humans on the evolutionary scale, according to a study published in the November 10, 2006 issue of Science. The study describes, for the first time, the sequence and analysis of the 814 million DNA bases that make up the genome of the purple sea urchin Strongylocentrotus purpuratus.
The scientists used a two-pronged strategy to sequence the urchin genome: whole-genome shotgun sequencing and a library of bacterial artificial chromosomes (BAC), clones that carry inside them very large pieces of sea urchin DNA. The NCRR-funded Sea Urchin Genome Resource at the California Institute of Technology provided the BAC library and the DNA for shotgun sequencing.
The sea urchin genome spells out about 23,300 genes. Surprisingly, genes previously thought to be unique to vertebrates also were found in the sea urchin. This realization will allow scientists to perform functional studies in a simple animal model that shared a common ancestor with vertebrates long ago.
