Tag Archives: academic life

A Blast from the Past

Sometimes you need a thick skin to be a scientist or scholar. Almost everyone, it seems, has encountered a reviewer who didn’t bother to read what you wrote or badly misunderstood what you said.

In other cases, you realize on reflection that a reviewer’s criticisms, although annoying and even painful at first, are justified in whole or in part. Addressing the reviewer’s criticisms helps you improve your paper or grant. That’s been my experience in most cases.

Sometimes, though, a reviewer just doesn’t like your work. And occasionally they can be pretty nasty about it. Here’s a case that I experienced on submission of the first paper about the Long-Term Evolution Experiment.

{You can click on the image of the review to enlarge it.}

Rev 1 of 1991 LTEE

A few choice lines:

“This paper has merit and no errors, but I do not like it …”

“I feel like a professor giving a poor grade to a good student …”

“The experiment is incomplete and the paper seriously premature …”

“I am upset because continued reliance on statistics and untested models by population geneticists will only hasten the demise of the field.”

“Since the Deans of Science at most universities can only count and not read, I can fully appreciate the reasons for trying to publish this part of the work alone.”

“Molecular biology … should be used whenever possible because molecular biologists control the funding and most of the faculty appointments.”

I’ve occasionally shared this with members of my lab when they get difficult reviews to remind them that it’s not the end of the world or their career, or even the paper that has been scorched.

PS The revised paper was accepted by The American Naturalist. In fact, it won the best-paper award there for the year in which it was published. It has also been cited well over a thousand times.

EDIT:  You can read my response to this review here.


Filed under Education, Science

When We’re Sixty Four (Thousand)

From the E. coli in the LTEE to the People of the Lab

[To be sung along to this Beatles classic]


When we get older, losing our fimbriae,

Many years from now,

Will you still be sending us our thiamine,

Birthday greetings, Erlenmeyer wine?

If we were mutants, crazy and fit,

Would that make you snore?

Will you still feed us, will you still freeze us,

When we’re sixty-four?


You’ll be older too,

And if you say the word,

We’ll evolve with you.


We could be handy, helping your pubs,

When your grants are gone.

You can write a paper by the fireside,

Weekend days give no time to hide.

Colonies growing, dotting the plates,

Who could ask for more?

Will you still feed us, will you still freeze us,

When we’re sixty-four?


Every summer you can buy a freezer when the space gets tight,

If it’s not too dear.

Save our clonal mix,

Plus and minus progeny,

Ara One to Six.


Keeping the notebook, pipetting each drop,

Track trajectories.

Indicate precisely what you think will change.

Hypothesize, test, unlimited range.

Give us your data, sequence and store,

Evolving evermore.

Will you still feed us, will you still freeze us,

When we’re sixty-four?



Filed under Education, Humor, Science, Uncategorized

Bacterial Niche Finally Defined

The following scholarly contribution comes from my wife Madeleine Lenski after conversing with her “sister” (my former postdoc) Valeria Souza.

For those with an itch for criteria,

Scratch this: What’s a niche for bacteria?

Don’t take me to task

If I answer “a flask” –

It’s a bitch from warm broth to Siberia.


January 19, 2016 · 9:08 pm

Representing Science to My Representative

My research is funded by the National Science Foundation, including the BEACON Center for the Study of Evolution in Action. BEACON is one of a dozen or so NSF Science and Technology Centers. Today, our Representative in the US Congress, Mike Bishop, came to BEACON for 40 minutes to discuss our center—what we do, what impacts our work has, and so forth.

It was something of a “fire hose” for Mr. Bishop, with several presenters trying to convey a lot of information very quickly.  However, he was engaged and asked thoughtful questions.  I think he left with an understanding of the importance of scientific and engineering research, including how fundamental curiosity-driven research can lead to applications.

I had 10 minutes to show him my lab and explain what we do and why.  When I make a short presentation like this one, I often write out a version in advance.  I don’t read it or memorize it by any means. However, writing it out helps get my thoughts in order—removing details that aren’t important, ordering ideas into a narrative, reminding me of what I most want to convey.

I’m sure I was not as clear or coherent as the text that follows.  I offer it here because it conveys the points I tried to make in the few minutes that I had as a representative of science speaking with a representative of the people.


I want to show you one of the experiments in my lab.  We call it the long-term evolution experiment. It’s an unusual experiment because it’s been running for over 27 years.  And we keep it going because it’s been a scientific goldmine leading to new discoveries about how bacteria change over time.

It’s important that we understand bacteria and how they evolve for many reasons. Bacteria are best known because some of them can cause dangerous infections. But many of them protect us against infections—if our guts were not filled with harmless bacteria, then the dangerous ones would have a much easier time getting established in our bodies. Some bacteria also provide nitrogen to plants and perform other essential functions in the environment, including degrading some of the wastes that we produce.  And some bacteria are the workhorses of biotechnology.

To give one example of why bacterial evolution is so important:  If bacteria didn’t evolve, we would have defeated nearly all the pathogenic bacteria on Earth with antibiotics.  But they do evolve and become resistant to our drugs, and so the pharmaceutical industry has to spend billions of dollars trying to keep up with the evolving bacteria and viruses by developing new drugs to treat infections.

It’s possible to see evolution-in-action in bacteria, like we do here, for several reasons.

  • Their populations are huge.  The number of bacteria in just one of these little flasks is comparable to number of people in the United States.
  • They grow really fast.  Every day, there are about 7 generations of bacteria in each of the flasks.  So each day we see the great-great-great-great-great grandkids, so to speak, of the bacteria that were in our flasks yesterday. After 27 years, the experiment has run for over 63,000 generations.
  • And one more important thing about bacteria. We can freeze them and bring them back to life, and so we’ve got a frozen fossil record of the experiment.

When I started the experiment in 1988, there was no human genome project, and not even a single bacterial genome had been sequenced.  Now we go into our freezers and sequence the bacterial genomes to see how their DNA is changing over time.

The work we’ve done in this curiosity-driven experiment has inspired others who are using similar ideas and approaches to understand the rates and mechanisms of how bacteria evolve.

I’ll give two quick examples that show how our NSF-supported fundamental science gets translated into applications that are important for security and health.

First, you remember the anthrax letter attacks on Congress that occurred right after the 9/11 attacks. In the first few days after the anthrax attacks, I was contacted by the Defense Threat Reduction Agency for advice on how to identify the source of the strain used in that bioterrorism, and how to distinguish it from other related strains. And in the months that followed, I was asked for and provided advice to the FBI and other agencies investigating the attacks. Tracking the source of microbes in outbreaks—whether natural or terroristic in origin—requires understanding how they change over time.

Second, my colleague Prof. Martha Mulks studies bacteria that colonize the lungs of people with cystic fibrosis (CF).  There are about 30,000 people with this disease in the US alone.  It’s an inherited disease that makes people susceptible to lung infections and, unfortunately, those infections kill many kids and young adults with CF.  Some of the bacteria that infect the diseased lungs are not pathogens to most of us—they’re bacteria that live in soil and on plants, but when they get into the lungs of CF patients they evolve and adapt to that new environment. They also evolve resistance to the antibiotics that are meant to get rid of them. How exactly the various bacteria change to become better adapted to the CF lung environment is not known. Luckily, though, Martha Mulks and other foresighted scientists and clinicians have kept frozen samples of these bacteria over the years—just like we’ve done with the long-term experiment I described a moment ago. Now the BEACON Center is supporting work by a graduate student, Elizabeth Baird, who will analyze the DNA from old and new samples and apply some of the same approaches and methods that we’ve used and developed for the laboratory experiment to see how the bacteria have changed—how they have become resistant to antibiotics and otherwise adapted to the environment of the lungs of people who suffer from cystic fibrosis.

The bottom line is that the fundamental, curiosity-driven research that the National Science Foundation supports is also an engine for future applications—often ones that we may not even have dreamed of—as well as a training ground for the talented and dedicated young people who you can see working all around us in this lab and throughout the BEACON Center.


Rep. Mike Bishop (MI-08) and me in the lab.  [Photo: Danielle Whitaker, MSU.]

Rep Mike Bishop and me in lab, 14 Oct 2015

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63,000 Strong

Ever wonder about those big numbers posted in a window in that tall building on the east side of Farm Lane, across from the entrance to the MSU Dairy Store?

Right now, the digits read 63000. That’s the number of generations in an experiment that’s been running in my lab for over a quarter century.

We call it the LTEE, which stands for the Long-Term Evolution Experiment. There are 12 populations of E. coli bacteria in the experiment, and they all started from the same strain.

Every day—weekends and holidays included—a member of my team takes 1% of the cells in each population and puts them in a flask with fresh food. Over the next 24 hours, the population grows 100-fold and then runs out of food. These dilutions and renewals go on day after day, week after week, month after month, year after year, decade after decade. I hope the experiment will continue long after I’m gone, so that someday someone can write “and century after century.”

Bacteria grow by binary fission: 1 cell makes 2 cells, 2 cells make 4, 4 make 8, etc. So the 100-fold growth in the fresh medium represents about 6.6 doublings, or generations, every day. (There’ve been some interruptions since the LTEE began in 1988, but not many.)

Now consider a bacterial cell that gets a mutation in its DNA that lets it acquire more food and grow a little faster. That cell will leave more descendants than its competitors—that’s adaptation by natural selection. Over time, the bacteria are becoming stronger and fitter in their flask-worlds.

By watching the 12 populations evolve, we can answer questions about the dynamics and repeatability of evolution in a group of organisms—bacteria—that are essential for life on Earth as well as important players in health and disease. We measure the growth rates of the bacteria, we sequence their DNA, and we see just how much evolution can achieve even in short order.

Oh, about the sign. Zachary Blount is a talented postdoc who works on this project, and he likes to have fun with science. He put up the window display which, if you look closely, has a picture of Charles Darwin on the left, “The E. coli Long-Term Evolution Experiment” over the number, and “Generations and Counting” to the right. Every 1,000 generations or so, Zack updates the sign.

63K window

[Photo credit: Zachary D. Blount]

Note:   This piece first appeared at eastlansing.org after an invitation from Alice Dreger to explain the numbers in the window to our community.

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Erdös with a non-kosher side of Bacon

Erdös number

Paul Erdös was a prolific and important mathematician. He also had hundreds of collaborators from around the world who coauthored papers with him.

Years ago, Casper Goffman explained an idea, called the Erdös number, that describes the “collaborative distance” between Erdös and someone else, where that distance is defined by the smallest number of steps based on coauthored papers. Erdös himself has an Erdös number of 0, while the 511 mathematicians who wrote papers with Erdös have an Erdös number of 1. One of these people is Persi Diaconis, a professional magician and Stanford mathematician specializing in probability theory.

Over 9,000 people have Erdös numbers of 2, meaning they wrote a paper with one or more of Erdös’s coauthors but never wrote a paper with Erdös himself.  Two of these people are Berkeley professors Bernd Sturmfels, in the field of algebraic geometry, and Lior Pachter, a computational biologist.  (Sturmfels coauthored three papers with Diaconis, and he wrote other papers with two more people with Erdös numbers of 1.  Pachter wrote several papers with mathematician Daniel Kleitman, an Erdös coauthor.)

In 2007, I coauthored a paper with Pachter and Sturmfels in which we analyzed epistatic interactions to describe the geometric structure of a fitness landscape:

Beerenwinkel, N., L. Pachter, B. Sturmfels, S. F. Elena, and R. E. Lenski. 2007. Analysis of epistatic interactions and fitness landscapes using a new geometric approach. BMC Evolutionary Biology 7:60.

So that paper gives me an Erdös number of 3.

Bacon number

A group of students later came up with the idea of a Bacon number, a Hollywood version of the Erdös number that equals the smallest number of film links separating any other actor from Kevin Bacon. (Bacon had been previously described as the “center of the Hollywood universe” after a 1994 interview in which he said he worked with everybody in Hollywood or someone who’s worked with them, according to Wikipedia.)

So Kevin Bacon has a Bacon number of 0, while actors who have appeared in a film with him have Bacon numbers of 1. An actor who appeared in a film with any actors who appeared with Bacon, but not in a film with Bacon himself, have a Bacon number of 2.

Morgan Freeman has a Bacon number of 1 based on a 2013 documentary film called “Eastwood Directs: The Untold Story.” (You missed that one? Me, too.) Well, a couple of weeks ago, I appeared in an episode of the show “Through the Wormhole with Morgan Freeman.”

Erdös-Bacon number

Now there’s a really special number called the Erdös-Bacon number, which is the sum of a person’s Erdös and Bacon numbers. Not many people have an Erdös number, and not many have a Bacon number. And very few people have an Erdös-Bacon number because you have to have written a math or science paper and appeared in a film, and of course with known connections to Erdös and Bacon along both paths.

Cornell mathematics professor Steven Strogatz has an Erdös-Bacon number of just 4, having appeared in a TV documentary film with Kevin Bacon called “Connected: The Power of Six Degrees.” Of course, that film is about the very sort of mathematical links we’re talking about here!

So someone just suggested to me that I now have an Erdös-Bacon number of 5. If so, that would put me ahead of such luminaries as Carl Sagan and Richard Feynman! Awesome!!

The fine print

As I was looking into this exciting possibility, I discovered a website called “The Oracle of Bacon.” It seems to be the semi-official arbiter of Bacon numbers, and it says: “We do not consider links through television shows, made-for-tv movies, writers, producers, directors, etc.”

That documentary about Clint Eastwood, with both Morgan Freeman and Kevin Bacon in it, apparently doesn’t qualify.  So Morgan Freeman’s Bacon number rises to 2 (via many different paths through his many major films).

Even worse, though, my Bacon number evaporates entirely, since my link to Kevin Bacon goes through my appearance on a television show with Morgan Freeman.

So there you have it. I have an officially non-kosher Erdös-Bacon number of 5.

I guess I can live with that.

But if Kevin Bacon, Morgan Freeman, or any of their Hollywood friends invites me to appear in a real film, I’ll probably accept!


Note:  It looks like Steven Strogatz’s Erdös-Bacon number of 4 is also compromised because his Bacon number is through a TV movie.  You need to use non-default settings for it to show up on The Oracle of Bacon website.  But maybe it’s less non-kosher, since it was a TV movie, not just a TV show.


Filed under Humor

Tiny Things that Live in Little Bottles

As I mentioned in my previous post, it can be a fun challenge to explain your scientific research to people who aren’t scientists.

A week or so ago I came across a website that challenges you to explain something complicated using only the thousand most commonly used words.

So here’s my effort about our long-term evolution experiment with E. coli:

My team works with really tiny things that live in little bottles. We watch the tiny things change over time – over a really long time. The tiny things that do the best have learned to eat their food faster and faster, before the other guys can eat their lunch, so to say.  Well, the tiny things don’t really learn, but it’s kind of like learning – and even better, the best ones pass along what they learned to their kids.  A really cool guy came up with the idea of how this works more than a hundred years ago. My team’s work shows he got it pretty much right. But there’s a lot of stuff he didn’t know, and we’re figuring that out, too.

Several other biologists followed up including Nicole King, Graham Coop, and Josie Chandler (the links are to the simple-words-only descriptions of their own research).

Give it a try, and add your contributions in the comments below!


Filed under Education, Humor, Science