Paddlefish X2

About 42 million years ago, the American paddlefish duplicated its entire genome, say researchers from San Francisco State University. In a new study in Genome Biology and Evolution, a team led by Karen Crow sequenced chromosomal regions containing 19 Hox genes in the fish, says an SFSU press release. They found extra genetic material indicative of genome duplication. Because Hox genes determine body shape and limb development, and because the paddlefish is often used as a proxy for a human-fish common ancestor, these findings may change the way researchers study how limbs evolved from fins, SFSU says. "Our findings suggest that the results of previous studies using paddlefish as a comparative species may need to be re-interpreted," Crow says. "This extra genetic material provides the canvas for evolution to paint with. … Our findings on the paddlefish suggest that whole duplication is not as uncommon in animals as previously thought."