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University of Pennsylvania evolutionary biologists have resolved a long-standing paleontological problem by reconciling the fossil record of species diversity with modern DNA samples.
Cataloging the diversity of life on Earth is challenging enough, but when scientists attempt to draw a phylogeny -- the branching family tree of a group of species over their evolutionary history -- the challenge goes from merely difficult to potentially impossible. The fossil record is the only direct evidence scientists have about the history of species diversity, but it can be full of holes or totally nonexistent, depending on the type of organisms. The only hope in such cases is to infer historical diversity from modern DNA sequences, but such techniques have a fatal flaw: the results they provide are demonstrably incorrect.
http://www.sciencedaily.com/releases/2011/09/110919151320.htm
Cataloging the diversity of life on Earth is challenging enough, but when scientists attempt to draw a phylogeny -- the branching family tree of a group of species over their evolutionary history -- the challenge goes from merely difficult to potentially impossible. The fossil record is the only direct evidence scientists have about the history of species diversity, but it can be full of holes or totally nonexistent, depending on the type of organisms. The only hope in such cases is to infer historical diversity from modern DNA sequences, but such techniques have a fatal flaw: the results they provide are demonstrably incorrect.
http://www.sciencedaily.com/releases/2011/09/110919151320.htm
