Genetic evidence is laying to rest a long-standing argument over the evolution of jawless vertebrates -- hagfish and lampreys -- and providing insights regarding the common ancestor of all vertebrates.
Sea lamprey
Image: Wikimedia commons
For years, biologists have debated the origins of jawless vertebrates -- molecular biologists have argued that molecular evidence shows they are each other's closest relatives, while morphologists maintained that detailed anatomical features suggest lampreys were more closely related to jawed vertebrates.In the most recent study, published Monday (18 October) in Proceedings of the National Academy of Sciences (PNAS), scientists on opposite sides of the argument looked at microRNA data, and found jawless vertebrates are indeed monophyletic, meaning they evolved from a common ancestor not shared by jawed vertebrates. "I was staggered by this paper," said linkurl:Philippe Janvier,; a paleontologist at the Muséum National d'Histoire Naturelle in Paris, France, and a long time supporter of...
A.M. Heimberg, et al., "microRNAs reveal the interrelationships of hagfish, lampreys, and gnathostomes and the nature of the ancestral vertebrate," PNAS,, 2010.

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