image: This is a simplified vertebrate phylogeny. This image relates to an article that appeared in the April 30, 2010, issue of Science, published by AAAS. The study, by Dr. U. Hellsten at Department of Energy Joint Genome Institute in Walnut Creek, Calif., and colleagues, was titled, "The Genome of the Western Clawed Frog Xenopus tropicalis." view more
Credit: Image © Science/AAAS