There are small petri dishes, there are large petri dishes, and then there is MEGA, an enormous, 2-foot-by-4-foot slab of black agar infused with a gradient of antibacterial drugs. Researchers built this behemoth to watch evolution in both time and space—and as they report today (September 8) in Science, MEGA has revealed that the fittest antibiotic-resistant bacteria may not necessarily grow the fastest.
On the oversized plate, “you can see evolutionary branching as it happens,” said Luke McNally, an evolutionary microbiologist at the University of Edinburgh, who co-authored an accompanying editorial. “It’s amazingly, strikingly beautiful.”
Researchers traditionally study bacterial evolution in liquid culture, which forces the bacteria to compete with the flask’s entire population for resources. By contrast, the new microbial evolution and growth arena (MEGA) plate separates bacteria both spatially and temporally, thereby reducing competition, said study coauthor Michael Baym of Harvard Medical School (HMS). The set-up shows the ...
