Jeffery E. Barrick and his colleagues have published the results of one of the most interesting evolution experiments I have ever read.1 Actually, the genius behind this experiment is Richard E. Lenski, who is on the author list as well. Lenski started an experiment with E. coli almost 20 years ago, and it is still producing excellent results. Essentially, the experiment followed twelve populations of E. coli over all those years. The focus of the paper was one of those twelve populations.
In the experiment, the bacteria were grown on a minimal medium with glucose as a limiting nutrient. Each day, a small sample of the culture was removed and placed in a fresh medium. Periodically, samples were frozen so that they could be analyzed in detail at any time.
Thanks to the wonderful technology we have today, the entire genome of E. coli can be sequenced in a “reasonably short” amount of time. So this paper reports on the results of comparing the genome of the original bacterium to that of the bacteria after 2,000, 5,000, 10,000, 15,000, 20,000, and 40,000 generations. The results were “rather surprising,” according to the authors.