This blog post is by MSU postdoc Zachary Blount.
Once upon a time, at a university far from MSU, Richard Lenski, my boss, founded twelve populations of E. coli from a single clone called REL606. And so began the E. coli Long-Term Evolution Experiment, or LTEE. Those twelve, initially identical populations have since been evolving under carefully controlled conditions in which, each day, 1% of each population is transferred to a fresh flask of medium. Under this regimen, each population goes through about 6.67 generations a day, and after more than 8,500 transfers, the populations have experienced more than 57,000 generations of evolution. That in itself is amazing, but this past Sunday the LTEE reached another, more human, milestone that more tangibly testifies to the patience and fortitude that has gone into the experiment. Rich performed the very first transfer of the experiment, the LTEE’s official beginning, on February 24, 1988, making the LTEE now 25 years old.
25 years! I don’t know about you, but I find that simply remarkable. In other labs, I have heard of experiments that go on for a week or two as being “long-term.” The LTEE redefines the term. 25 years. A quarter century. It is striking to consider that the experiment is now older than all the undergrads who help us in the lab, and even older than one of the graduate students! How amazing is that? At some point, we will need to start adding “venerable” to the name, as in The Venerable Long-Term Evolution Experiment!
Anniversaries offer, by their nature, both times and excuses to reflect and wax philosophical, and so it has been for me at this anniversary. Among other things, it underscores something that continues to provide me with a sense of both amazement and deep meaning. This is an experiment that, for all of us in the lab save Rich, was here before we came, and which will continue long after we leave. It is a constant thread running through the times of all the changing members of the Lenski lab. All of us, in one way or another, are participants in a grander story that is written by each of us in turn. (Indeed, because more than one LTEE worker was inspired to study experimental evolution by the LTEE itself, this is a story that creates its own writers!) I have taken great power and solace from that fact. In times of frustration with my work, when I might otherwise be tempted to just give up on a line of inquiry, I have known that it isn’t just me that I am working for, and thereby found new resolve. Yes, that is always true, or at least it should be, in science, where we are all in a sense working for humanity, but in the Lenski lab, working on the LTEE, there is a greater sense of the immediacy of this fact. I know that I am a part of a line of great workers on a grand experiment that is daily shedding light on hidden corners of evolution that might not otherwise be illuminated. I know that my work adds to the accumulated findings of that experiment, and that it will provide further foundation to those who come after me. This sense of continuity and communal effort adds a great deal to the wonderful experience of working in this great lab.
In 2005, about a year after I joined the lab, we celebrated the LTEE’s “Sweet 16,” based on the years of transfers that had been made. I decided to indulge a hobby of mine to celebrate the event, and so I made a calligraphy that I designed to express the community and continuity of the experiment. The calligraphy listed those who had worked in the lab since the experiment began to express the community. It also featured a graphic depiction of the experiment, with twelve lines extending from a circle representing REL606, and streaming down the page, the years ticked off to the left, and the generations of evolution experienced to the right. While I was coming up with this design, I realized that both the lab and the experiment really embodied the inverse of one of the mottos on the Great Seal of the United States: “E pluribus unum,” which is Latin for “One from many.” Being one who bears deep love for ancient history, and consequent respect for Latin mottos, I unilaterally decided on a motto of the LTEE for me to put on the calligraphy: “Ex una plures,” or “Many from one.”
As time has gone by, I have come to see this motto as appropriate on levels I had not originally considered. Originally, of course, it came from how there were twelve lines that came from a single cell, but it is really more than that. From one person, Rich, came many students, both graduate students and undergrads, many postdocs, and many associates in collaborating labs. One mind’s product led to the products of many minds. One idea led to many. One experiment yielded many others. One set of questions led to the asking of many others. One paper led to many. Even more so, I think “Ex una plures” is also that it is a good motto for evolution, so that those simple words and the concept behind them describe both the greater phenomenon, and the microcosm meant to allow its study. From one population of identical cells, existing under a single environmental condition, cycling predictably, though the chance and contingency infused process of evolution, came many different cell lines existing in their own little tangled banks, each with its own quirks and unique features. It echoes the great and poetic line with which Darwin closed On the Origin of Species:
“There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.”
I am waxing lyrical, I know. What I am trying to say is that this anniversary has made me reflect on just how wonderful, profound, elegant, and, yes, incredibly beautiful this experiment is! I consider myself so very lucky, indeed blessed to work on and be a part of it, and for that I am profoundly grateful. So happy birthday, Long-Term Lines! May your days continue onward uncounted, and your story never end!