Long-term lab experiment traces a trait's reappearance
Big leaps in evolution are the products of tiny genetic changes accumulated over thousands of generations, a new study shows.
E. coli bacteria growing in a flask in a lab for nearly 25 years have learned to do something no E. coli has done since the Miocene epoch: eat a chemical called citrate in the presence of oxygen. Evolutionary biologists Zachary Blount and Richard Lenski of Michigan State University in East Lansing and their colleagues describe the molecular steps leading to the feat online September 19 in Nature.
The work demonstrates that