This Week's Citation Classic

I am a little late with the post, but there's been a perfect storm of conflicting obligations. Without further ado, here is this week's citation classic:

Lenski, R. E., M. R. Rose, S. C. Simpson, and S. C. Tadler. 1991. Long-term experimental evolution in Escherichia coli. I. Adaptation and divergence during 2,000 generations. American Naturalist138:1315-1341.

The field of experimental evolution is a surging one; many scientists have seen that they can observe the process of evolution in real time using microbes and other model organisms. Jacques Monod's aphorism, "anything that is true of E. coli must be true of elephants, except more so", can be extended to say that evolutionary processes are the same for E. coli as they are for elephants.

Lenski et al. recognised this and initiated one of the longest experiments in evolutionary biology history. At the time of publication, 12 populations initiated from a single E. coli ancestral strain had undergone 2,000 generations of evolution and adaptation. ~20 years later, the group is up to 40,000+ generations. The initial environment was a poor one, a restricted diet of glucose, but the beasties have responded to this challenge vigorously, and because Lenski and team have saved individuals from various times during the experiment, the process of adaptive evolution can be traced via this "frozen fossil record".

Lenski et al.'s experiments have proved to be enormously informative, have generated 40+ publications and have launched the careers of numberous graduate students and postdocs. Indeed an entire Gordon Conference is devoted to the subspecialty, Microbial Population Biology, and a substantial number of attendees are Lenski's intellectual descendants.

On a personal note, when I was in graduate school, my mentor suggested that I model my career after a successful scientist. "Who?", I asked. "How about Rich Lenski?" I then downloaded all of Lenski's papers and read, for the first time, about the fascinating series of experiments that began with the present classic. Inspired, I soon dropped my researches into the population biology of mosquitoes (well I was looking for justification to do so anyway ;) and dived into the field of experimental evolution. When it came time to seek out postdoctoral mentors, I queried Dr. Lenski, but unfortunately his lab lacked funding for a postdoc. He did, however, suggest his former grad student, Dr. Paul Turner, whom I began working for in 2003. And the rest is history...

Carl Zimmer wrote about the experiments for the Science Times here. Another interesting article is available from Science. A website dedicated the the long-term evolution experiment is available here. And Rich Lenski's lab page is here.

Photo of Rich Lenski courtesy of Bruce Fox, MSU.