Lenski’s E. Coli Experiments

Bacteria Makes "Major" Evolutionary Shift in Dr. Lenski's Lab, is the headline of a recent New Scientist article. An interesting paper has just appeared in the Proceedings of the National Academy of Sciences, It is the "inaugural article" of Richard Lenski, who was recently elected to the National Academy. Lenski, is well known for conducting the longest, most detailed "lab evolution" experiment, growing the E. coli bacteria continuously for about twenty years in his Michigan State lab. For the fast-growing bug, that's over 40,000 generations! E. coli you may recall is the bacteria that are often cited as the cause for food poisoning in humans. Here is an article in New Scientist that discusses the Lenski experiments: http://www.newscientist.com/channel/life/dn14094-bacteria-make-major-evolutionary-shift-in-the-lab.html;

 

So does this mean the end for Intelligent Design? If a major evolutionary change can take place described as "the first time evolution has been caught in the act of making such a rare and complex new trait", doesn't this doom any claims that Darwinism is wrong? Well, I don't think this is much of a story for a number of reasons. But let me first describe what the Lenski experiments show, and then I will later explain why this is exactly what was described in Prof. Michael Behe's (pro-ID) 'Edge of Evolution' book.

 

The Lenski experiment is fascinating. He examined trillions of E. coli bacteria cells, over 20 years time, resulting in over 44,000 generations. What he did was set up 12 different groups all descended from the Adam E. coli parent. All of the groups developed along similar lines in the ideal lab: they all evolved larger cells; and all developed faster growth rates on the glucose that they were fed. But one of the 12 test groups developed a unique trait – the ability to metabolize citrate, which was a second nutrient (besides the glucose) in all of the cultures. And when the "evolved" E. coli developed the ability to metabolize citrate, it was a beneficial new trait that allowed this group an advantage over the other 11 groups because of its growth in population size.

 

So was this really a "major" evolutionary shift? Was it the development of a new leg, or a proto-eye? What was the "complex new trait" that the E. coli bacteria developed after 40,000 generations? Yes, this "profound change" meant that it could "metabolize" citrate. The article makes it sound like it is a big deal. But consider that E. coli is normally capable of utilizing citrate as an energy source under anaerobic (without oxygen) conditions, with a whole suite of genes involved in its fermentation. In addition, the Krebs cycle (or citric acid cycle, where chemical reactions create energy for the cell to use) for E. coli already generates and utilizes citrate in its normal metabolism of glucose and other carbohydrates. Now is this really a big deal? It doesn't seem like it's a major new step – instead, it appears to be just the re-tooling of machinery inside the E. coli that is already there. Here is the way Prof. Behe describes it: "the wild bacterium lacks an enzyme called a "citrate permease" which can transport citrate from outside the cell through the cell's membrane into its interior. So all the bacterium needed to do to use citrate was to find a way to get it into the cell. The rest of the machinery for its metabolism was already there."

 

So there you have it – The E. coli's major evolutionary shift is to allow citrate to be transported inside the cell membrane so that it can be used. All of the machinery to use citrate was already inside the cell. Yawn, excuse me while I go to sleep…

 

The real question is why are the Darwinists making such a big deal about this? It's obviously because Prof. Behe's pro-ID book "Edge of Evolution' has drawn blood on the dying, critically wounded Theory of Evolution. Louisiana just this past week passed a bill to teach Darwinism critically (like Texas before it), and this seems like it is a growing trend. And the Darwinists will use anything to try and show that observed major evolutionary changes really do take place. That's all well and good, but we still haven't seen any major changes, and the Lenski E. coli experiments certainly are not Darwinism's savior.

 

Instead, this looks like it is exactly along the lines of what is described in Prof. Behe's 'Edge of Evolution' book, where he describes malaria's resistance to drugs used against it, as well as HIV's evolving resistance. In fact, chapter 7 of EoE Prof. Behe actually describes and uses the Lenski experiments in support of his position. He placed the Edge of Evolution at three successive mutations. And the way it is described in the New Scientist article, this appears to be exactly what took place in the Lenski E. coli experiment – one change took place in one of the 12 groups after 20,000 generations. And the new trait was discovered after 30,000 generations. Although there are no details learned of what genetic changes took place, it sounds like these are successive, single point mutations building upon each other, perhaps up to three mutations working together. Professor Behe's full Response is posted in his Amazon blog, which can be found at: http://www.amazon.com/gp/blog/post/PLNK3U696N278Z93O; Thus, it seems just like the other genetic studies reviewed in Prof. Behe's book – no new major evolutionary changes. Instead, just minor mutations that eventually provide a small benefit.

 

So, those of you who distrust the Darwinist fairy tale description of how life developed on Earth, commonly known as Evolution, you have nothing to fear from what is contained in the Lenski E. coli experiments. And it looks much more supportive of Intelligent Design than it does of Darwinism. Here are a few of the reasons why I say this:

 

• Trillions of cells evolving over 30,000 generations? Look at the math! For humans to evolve anything during this same period (30,000 generations), would be the equivalent of 600,000 years (30,000 generations averaged over 20 years time, a rough estimate of an adult generation). And the ability to metabolize citrate is all that was developed? Darwinism is not at all an effective explanation for how life developed on Earth. Too little change and not enough time. As one blogger writes – "Presumably, the same mechanism that gave E. Coli citrate capability turned a primitive simian ancestor into Beethoven, with orders of magnitude fewer probabilistic resources." This problem of Darwinism sounds very persuasive to me;
  
• It looks like mutations that hurt the cell are much more numerous than any possible benefits. Prof. Behe claims that all of the E. coli mutations in the Lenski study are "degradative" (see Behe link, above), making the cells less active. This makes for the exponentially more difficult problem of Darwinism to make for a beneficial mutation;
  
• The straightforward ID prediction is that any experimentally demonstrated change in the genome of E. coli will be limited to two, or at the most 3 separate steps, unless the steps can be demonstrated to be sequentially more fit. That's a scientific prediction, if you will, which would seem to make ID a scientific theory. Where are the Darwinists to show that this prediction is wrong?
  

 

Keep the faith! Happy birthday to my child no. 3, and to me, Jeanne, and Boy George. Enjoy Father's Day tomorrow, all you fathers out there.