One small step for a bacterium…

…one giant leap backwards for man.

A recent paper out of Richard Lenski‘s lab at MSU details the evolution of a Cit+ strain of E. coli among the 12 replicate lines that are part of the Long Term Experiment in Evolution running in his lab

I haven’t read the paper yet, but from the abstract, it seems the evolution of a relatively radical new trait (for E. coli) which is the utilisation of citrate as a carbon source has been demonstrated and also it is shown that this trait was contingent on the “history” of that particular line that developed the trait. Essentially, the other 11 lines did not gain the ability to use citrate even on subsequent experiments with earlier generations, but the line that did evolve could do so again and again from earlier generations that didn’t have the ability.

Understandably, this is an important study in evolution for the role of historical contingency (read “chance”) but also in demonstrating that an ability (or lack of) that partially defined the species in question had evolved in the lab.

But more on that in another blogpost.

What has struck me about the news surrounding this paper on the net has been the vigour with which the results, the science (and sometimes even the scientists) are been questioned and attacked by what I can only charitably call the “god” brigade.

Part of the reason could possibly be because of the way the New Scientist article about the paper ends:

Lenski’s experiment is also yet another poke in the eye for anti-evolutionists, notes Jerry Coyne, an evolutionary biologist at the University of Chicago. “The thing I like most is it says you can get these complex traits evolving by a combination of unlikely events,” he says. “That’s just what creationists say can’t happen.”

That one short paragraph seems to have got their collective goat and has led to a flood of comments on the New Scientist site. The giant leap backwards is that a lot of the people commenting seem rational, coherent and somewhat aware of the biology but somehow perversely blind to the idea of evolution.

The old chestnuts about micro-evolution and macro-evolution are trotted out numerous times as well as variants of “But it’s still a bacterium” not to mention “It’s all random therefore we are random.”

A quick sampling of some of the inane comments:

Back on topic, i’m a more logical guy so I think things through. There’s no black and white, noobs.

Anyway, personally, it seems to me the mutation at generation 20,000 could be evolution (however, evolution refers to advantage, and until this scientist figures out what REALLY happened, we don’t know if that change was technically advantageous or disadvantageous. I think we can assume advantages since they survived. Survival of the fittest, right?)

However, I see this article fails to mention epigenetics!! Epigenetics very well could be the CAUSE of the WHOLE series of changes, OR, there was a random mutation first (evolution), which made it easier for epigenetics to take over, causing the Cit+ trait.

Sigh. Where do you begin with comments like that?

On the other hand if the basis of evolution is randomness, then that destroys the entire foundation that science is built upon. The evolution to human beings is also random. What we see and think are also therefore random. All our theories are therefore random. We cannot really be sure whether we have really evolved or not, if we base evolution on randomness, since everything is random. We cannot even be sure that we are thinking, after all it might be just some random hallucination. We cannot be sure of anything. One cannot build a rational world on disorder.

Oh wow.

This article doesn’t explain why this is a a major innovation.

A flagellum would be major.

I suppose if someone WERE to demonstrate the evolution of a flagellum it would be dismissed as not major. Like clockwork, the next comment states:

Even a flagellum would not be major. If evolution is responsible for all biological structures — and that is a BIG IF — then the human brain, which is capable of advanced mathematics, language, and philosophy, is evolution’s greatest triumph.

And to end:

What Bothers Me Most Is that the evolutionary biologist at UC has already formed a conclusion before the initial research has been completed and published. This doesn’t seem very scientific of him, or the article for quoting him. I kind of get the impression that New Scientist has a chip on it’s shoulder when it comes to creationist. There are loads of “theories” out there on a milieu of topics, which aren’t accepted by the scientific community at large (creationism obviously falls into this category), yet NS seems to single creationism out for needing repeated condescension…

I guess 20 years of experiments and published papers don’t count for squat?


  1. Nash says:

    Oh boy, his experiment counts as a fail.

    Since there turned out to be one strain that evolved Cit+ness reproducibly , and others did not – this means that there were already on some hidden(to us) biochemical or molecular level, two distinct species – one that had the potential to evolve Cit+ness and the other not.

    In this light, the experiment does not show speciation, but merely the fact that variation can occur – which is not exactly news.

    In any case, for bacteria and many other simple asexually reproducing organisms the concept of “species” is a not discrete, but a continuum. The test for speciation in the lab would be variation that leads to reproductive isolation , and thus splitting of a single population into two distinct populations with no chance of creating a hybrid progeny.

  2. Ashwan says:

    Considering that all 12 lines had the same ancestor, where did that “hidden species” come from?

    Of course, Lenski isn’t claiming this is speciation at all, but nevertheless it’s a demonstration of a new trait evolving when previously there wasn’t one.

    This is now an “old” paper, earlier this month they published new work where they sequenced the genome of the different lines and also ancestral ones to figure out what genetic changes occurred.

    (Don’t have a link to the paper from Nature unfortunately and I haven’t read it yet myself.)

  3. Ashwan says:

    You bring up a good point about speciation for bacteria. In fact the strain used in these experiments did not carry the F plasmid and so reproduction was completely asexual.

    But they did carry out experiments that showed that in the “evolved” line recombination with the ancestor was inhibited and thus demonstrated “incipient speciation”

  4. Nash says:

    Now that I read the articles, I understand that what is new here is not that traits evolve, but an understanding of how difficult it can be to tease out the effects of nature and nurture on evolution.

    By the way, kudos for having the patience to run a 21 year experiment.

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