Evolution: Take Two

Eric Gaucher and Betül Arslan at the Georgia Institute of Technology are trying to determine whether a 500 million-year-old bacterial gene will evolve the same way twice, given the chance to start over, says New Scientist's Bob Holmes. The researchers are working with a gene called EF-Tu, which plays a role in protein synthesis in E. coli. Gaucher had previously estimated the gene's age, and Arslan has now synthesized the gene in its ancient form, inserted it into modern E. coli colonies, and let the bacteria evolve, Holmes says. "When Arslan sequenced their genomes, though, she found that EF-Tu was unchanged, Holmes adds. What had evolved — differently in each lineage — were the genes that interact with EF-Tu." The experiment will continue, so the researchers can determine whether EF-Tu itself will evolve the same way it did 500 million years ago. "The experiment may help biologists understand the extent to which evolution is predictable," Holmes says.