Today’s Pick: Evolution under the microscope
E. Coli, courtesy Wellcome Images
While the rest of Michigan fixated on the Democratic primary’s delegate math, Richard Lenski of Michigan State witnessed evolution.
Lenski has spent the past 20 years observing the development of 44,000 generations of bacteria in 12 genetically identical E. coli populations. After about 31,500 generations, one population developed the ability to metabolize citrate — something that E. coli can’t normally digest.
Turning to his “fossil record” — frozen samples of previous generations — Lenski was able to replay bacterial development. The New Scientist explains, “The replays showed that even when he looked at trillions of cells, only the original population re-evolved Cit+ – and only when he started the replay from generation 20,000 or greater. Something… must have happened around generation 20,000 that laid the groundwork for Cit+ to later evolve.”
Lenski himself takes a more philosophical view of the results (and proves that science and great writing can coexist), poetically concluding,
“In any case, our study shows that historical contingency can have a profound and lasting impact under the simplest, and thus most stringent, conditions in which initially identical populations evolve in identical environments. Even from so simple a beginning, small happenstances of history may lead populations along different evolutionary paths. A potentiated cell took the one less traveled by, and that has made all the difference.”
Kathryn is the Market Research Information Specialist Intern at MaRS. She is a graduate of the Masters of Information Studies program at the University of Toronto.