Today is the 32nd birthday of the E. coli long-term evolution experiment (LTEE). I started it on February 24th, 1988, when I was at the University of Califonia, Irvine.
It also happens to be daily transfer number 11,000 for the experiment. But wait, you ask: Is 365 x 32 really equal to 11,000? (Not to mention the complication of leap years.)
No! 365 x 32 = 11,680. We’re almost 2 years behind perfection! Over the years, we missed daily transfers for various reasons including the fact the experiment was frozen for several months around the time of my move from Irvine to Michigan State University, as well as some missed transfers and various mishaps (including contamination) along the way that have led us to restart the experiment from frozen samples.
Luckily, we don’t have to go back to the beginning–the LTEE wouldn’t have survived if we did. We freeze whole-population samples every 75 days, and those provide the backups that keep us going when needed.
So the LTEE is 32 years old today. The evolving bacteria lineages, though, are younger, at a little over 30 years (11,000 / 365). I prefer to think of them as timeless, though … having survived in and adapted to their tiny flask worlds for more than 73,000 generations.
Here’s grad student and lab manager Devin Lake doing today’s transfer.
And here’s Devin & me with the lab notebook. Devin is pointing to today’s entries.
And here’s what we wrote:
For those with pathogens on their mind (and that’s a lot of us, with the new coronavirus spreading), you might wonder: Aren’t E. coli dangerous? The short answer is only rarely. All of us have harmless or even beneficial strains of E. coli and many other bacterial species in our GI tract. The LTEE uses one of these harmless strains, one that has been studied in many labs for close to a century without problems. There are some strains of E. coli, though, that are nasty, and which are usually acquired by eating contaminated foods. So wash your raw fruits and vegetables, cook your meats, and don’t worry about the LTEE bacteria … Just wish them a happy birthday today, and many more years of scientific discovery.