November 9, 2006—They might be small, spiky, and spineless, but they're still family.
In fact, California purple urchins share more than 7,000 genes with humans, making them closer cousins to us than are fruit flies and worms, animals more commonly used as models in genetics research.
This unexpectedly direct connection between humans and sea urchins—one of the few invertebrates on our branch of the evolutionary tree—is just one of the findings revealed by the recent sequencing of the sea urchin genome.
A description of the achievement, along with several related studies, will be published in tomorrow's issue of the journal Science. (Read "Sea Urchin Genome Reveals Striking Similarities to Humans" [November 9, 2006].)
Gary Wessel is a biology professor at Brown University in Providence, Rhode Island, and a member of the Sea Urchin Genome Sequencing Consortium. Like many other scientists, he has used the marine animals for decades as models to study human processes such as fertilization and embryo development.
"We've already learned an enormous amount from the sea urchin, from something as basic as how identical twins form to in vitro fertilization procedures," Wessel said in a university press release.
"With a complete map of the urchin's DNA, we can now learn more quickly and easily how each process works during development."
The results of the genetic sequencing also held an unusual surprise for Wessel: The eyeless urchins can see. Genes associated with vision are active in the urchins' tube feet, suggesting that their limbs can sense light.
"Nobody would've predicted that sea urchins have such a robust gene set for visual perception," Wessel said. "I've been looking at these organisms for 31 years—and now I know they were looking back at me."
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