Pharyngula

2 + 2 = 17, for certain values of 2

A while back, I responded to Behe/Luskin’s claim that his model proving the impossibility of evolution of chloroquinone resistance was vindicated. I pointed out (as did Ken Miller) that showing that a particular trait required multiple point mutations did not affect the probability in the naive way that Behe and Luskin calculated — in particular, it did not require that the mutations be simultaneous. We’re familiar with a great many known mutations that involve multiple sequential hits to have their effect. I mentioned the work on steroid receptor evolution, and how cancer is an amazing example of the power of the accumulation of sequential variants.

Behe fired back, issuing a challenge to ‘show my numbers’. If he could have said anything to confirm that he was obliviously ignoring my point, that was it, and so I blew him a raspberry and ignored his challenge. I wasn’t arguing with his numbers, and we could even use his very own set of numbers — my point was in the operation he was doing with those numbers. His assumption is that you must have two mutations occur simultaneously, in the same individual, so that you simplistically multiply the probabilities together to get an improbably low frequency. I’m saying that’s invalid: these mutations can happen independently, they can accumulate to some frequency in the population, and then a second mutation can occur.

Now Larry Moran has carried through on the calculations. Using the known data on mutation rates, and throwing away Behe’s bogus demand that everything occur in the very same instant, he shows that the evolution of chloroquinone resistance ought to be rare, but not at all impossible, and with frequencies that are in the ballpark of what is observed.

Furthermore, Moran describes a paper that quantifies the presence of malaria strains in the population that contain pieces of the resistant combinations and that further describe the sequential series of mutational events that led to the most resistant strains.

All of the strains (except D17) are found in naturally occurring Plasmodium populations and the probable pathways to each of the major chloroquine resistant strains are shown. It takes at least four sequential steps with one mutation becoming established in the population before another one occurs.

None of the mutations occurred simultaneously as Behe claimed in his book.

The intelligent design creationists are somehow still crowing victory. I don’t quite understand how — their premises have been demolished, they’ve been cut off at the knees, but I guess their followers are easily bamboozled if they shout “math!” loud enough. Even if the math is wrong.

Comments

  1. #1 Jason Nishiyama
    August 2, 2014

    I would posit that their followers aren’t particularly good at maths, aiding in the bamboozling…

  2. […] Source: 2 + 2 = 17, for certain values of 2 [Pharyngula] […]

  3. #3 Ashley Carter
    CSULB
    August 3, 2014

    A few years ago (2002) I wrote a paper about this. Acquisition of pairs of mutations can occur even when possessing single mutations is deleterious and is faster in larger populations like mosquitoes. Here is a direct link to the paper and the math is actually fairly straightforward:

    http://www.csulb.edu/~acarter3/pdfs/carter-wagner-ProcRoySocB2002.pdf

  4. #4 Paul
    August 3, 2014

    Of course math doesn’t matter to them, it all has to happen at once and is therefore a miracle .

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