Pseudomonas fluorescensWIKIMEDIA, RIRAQ25Bacteria that lack a vital protein for growing flagella—tail-like structures that enable the microbes to swim—can attain flagella in as little as four days given enough pressure to evolve, according to a paper published in Science today (February 26). Furthermore, this fast fix evolves in nearly the same way in each independent strain: through the repurposing of a distantly related protein.
“This is a fascinating set of evolution experiments,” wrote evolutionary biologist Richard Lenski of Michigan State University in an e-mail to The Scientist. “Their experiments show how a biological function—in this case, flagellar motility in Pseudomonas fluorescens—can re-evolve after the deletion of a seemingly critical gene. The bacteria regained motility not by reacquiring the lost gene . . . but instead by mutations in other genes that put their products to new uses.”
There are still some big unanswered questions about evolution, such as “how major evolutionary changes take place,” said Austin Hughes of the University of South Carolina who, like Lenski, was not involved in the work. “It relates to the old debates going way back between gradualism and saltation,” Hughes said. That is, ...
