Intelligent Design

Molecular biology: The Bloom’s complex mousetrap

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Nature 456, 453-454 (27 November 2008) | doi:10.1038/456453a; Published online 26 November 2008

Robert M. Brosh, Jr

Genomic instability often underlies cancer. Analyses of proteins implicated in a cancer-predisposing condition called Bloom’s syndrome illustrate the intricacies of protein interactions that ensure genomic stability.

Bloom’s syndrome, which is characterized by severe growth retardation, immunodeficiency, anaemia, reduced fertility and predisposition to cancer, is caused by mutations in the gene BLM. At the cellular level, the hallmark of this genetic disorder is a high rate of sister-chromatid exchange — the swapping of homologous stretches of DNA between a chromosome and its identical copy generated during DNA replication

Robert M. Brosh Jr is in the Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, NIH Biomedical Research Center, Baltimore, Maryland 21224, USA.

Email: broshr@mail.nih.gov

2. “The BLM protein complex consists of several components, much like a mousetrap. With all the parts properly assembled, the mousetrap will operate efficiently and catch the mouse. In this case, a DNA structure called a double Holliday junction is caught in the BLM complex. Xu et al. and Singh et al. report the discovery of a component of this complex, RMI2, which stabilizes and orchestrates the action of the BLM complex, ensuring resolution of the double Holliday junction, and so promoting chromosomal stability.”

3. “As for the significance of RMI2 to the BLM complex, for analogy let’s imagine a mousetrap. It contains several components, including a spring, a platform, a hammer, a hold-down bar and a catch. Omit certain components of the trap, and the device may still operate, albeit less efficiently. With all of the components in place – including those with primarily structural roles such as the hold-down bar and the platform – the trap is most likely to catch the mouse. Returning to the BLM complex: through its interaction with RMI1, RMI2 allows the ‘BLM–Topo-3alpha device’ to assume optimal stability and configuration so that it can efficiently catalyse the splitting of the double Holliday junction, and so prevent the escape of deleterious DNA structures that would lead to crossovers (Fig. 1). RMI2 therefore seems to have an integral structural role in the BLM–Topo-3alpha device by orchestrating its action.”

This is made relevant by Behe’s observation that “Darwinian scenarios, either for building mousetraps or biochemical systems, are very easy to believe if we aren’t willing or able to scrutinize the smallest details, or to ask for experimental evidence. They invite us to admire the intelligence of natural selection. But the intelligence we are admiring is our own.”

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14 Replies to “Molecular biology: The Bloom’s complex mousetrap

  1. 1
    ribczynski says:

    Mario,

    Where does quote #4 come from? I couldn’t find it in the article.

  2. 2
    RoyK says:

    Rib [1], Neither could I. Please attribute properly.

  3. 3
    RoyK says:

    My second sentence above is of course directed not at Rib but at Mr. Lopez.

  4. 4
    RoyK says:

    I’m curious where Mr. Lopez got the last quote from. It’s not from the article, as should be obvious. But most readers would have to pay for access to the full article. Why should I be generous and not simply call this post a flat-out falsehood?

  5. 5
    RoyK says:

    Does somebody need to call Mr. Belding?

  6. 6
    AussieID says:

    Mario, the way this post has been written is probably a little confusing. I concur with your throughline, but Point 4. does look as though it has been written by the author of the article, where in fact it was written by Michael Behe in an article I knew and have used in the past: “A Mousetrap Defended:
    Response to Critics”. It’s online at: http://www.arn.org/docs/behe/m.....fended.htm

    An addendum would suffice, I believe, to make a connection between the author of the article – Brosh – and how you hoped to entwine Behe’s summation from the article.

    Just a thought for purposes of clarity …

  7. 7
    PhilipBaxter says:

    This is made relevant by Behe’s observation that “Darwinian scenarios, either for building mousetraps or biochemical systems, are very easy to believe if we aren’t willing or able to scrutinize the smallest details, or to ask for experimental evidence. They invite us to admire the intelligence of natural selection. But the intelligence we are admiring is our own.”

    It seems to me that

    a) They have provided experimental evidence, otherwise what is being described in the article?
    b) They have scrutinized the smallest detail, otherwise what is being described in the article?
    c) Omit certain components of the trap (The BLM protein complex), and the device may still operate, albeit less efficiently. Does this not invalidate Behe’s mousetrap example somewhat?
    d) Where, specifically, have they invited us to “admire the intelligence of natural selection”?

    After all, no doubt there are systems as complex, more complex, less complex everywhere. We’ll no doubt be documenting such systems in the same way species have been discovered, for years to come.

    Are you saying that each such complex discovered is the product of a seperate instance of intelligent intervention?

    That the, trillions upon trillions of such systems (all over the world, all over the galaxy no doubt, then the universe) are all designed?

    Seems to me the sensible thing to so, if such systems were desired would be to set them up so that they generated themselves, perhaps by enabling them to repoduce and combine in slightly different ways, you’d eventually get a diverse range of systems each “designed” for the task at hand.

    Seems much less work to me!

  8. 8
    sparc says:

    comments #1-#6 seem to belong to another thread.

  9. 9
    TheYellowShark says:

    “comments #1-#6 seem to belong to another thread.”

    Mario edited the post without any indication of having done so. The Behe quote at the end was originally attributed (intentionally or otherwise) to the author of the Nature article.

  10. 10

    My apologies to everyone. Thank you, AussieID, for pointing to the source of that last quote. The original blogger on this is found here:

    http://pos-darwinista.blogspot.com/

    –Mario

  11. 11
    lukaszk says:

    PhilipBaxter: “all over the world, all over the galaxy no doubt, then the universe”, especially “all over the galaxy no doubt” – what makes you think this way? In the fact, there is no evidence of ANY live outside Earth and the probability is telling us that the life on Earth is a big surprise. Maybe you have newer facts about it? Please, type them here.

  12. 12
    magnan says:

    “As for the significance of RMI2 to the BLM complex, for analogy let’s imagine a mousetrap. It contains several components, including a spring, a platform, a hammer, a hold-down bar and a catch. Omit certain components of the trap, and the device may still operate, albeit less efficiently.”

    I fail to see how how eliminating any of the elementary components enumerated would do anything other than completely disable the trap – hardly leaving it still functional but less efficient. The article writer seems to be presumptuously assuming that “irreducibly complex” machines are ultimately really not, contrary to basic logic and common sense.

    RMI2 appears to be more like a refinement to the basic BLM mechanism that enables it to work more effectively, analogous to refining the mousetrap design with a better designed hold down bar and catch that is very resistant to accidental triggering. The basic BLM mechanism is probably irreducibly complex in the mousetrap sense.

  13. 13
    Domoman says:

    Lukaszk, you quoted PhilipBaxter and said,

    PhilipBaxter: “all over the world, all over the galaxy no doubt, then the universe”, especially “all over the galaxy no doubt” – what makes you think this way? In the fact, there is no evidence of ANY live outside Earth and the probability is telling us that the life on Earth is a big surprise. Maybe you have newer facts about it? Please, type them here.

    You raise an interesting point. Many people seem to assume that life will be found, and is indeed on other planets. Yet this is based simply on the religion of naturalism. Basically, this religious belief is: life isn’t that hard to get by chance (or, if it is hard to get by chance, it’s likely it will happen due to there being so many planets in the universe), and is a byproduct of nature, so of course there will be life on other planets. Yet we have never found life on other planets, and we have no reason, as of yet, to suggest we will find it.

  14. 14
    lukaszk says:

    Domoman – that’s right. And I will tell more…

    A probability of life creation without intervention of any power can be shown as 1*10^(-n), where the lowest counted n (AFAIK) is 700. Even if we ‘cut’ some levels of n (lets say.. 80 – let each atom in the universe has his own planet Earth), we have n=620 and Prob = 1*10^(-620) – impossible.

    In UK there were buses with ‘There probably is no God’, right? It should be changed to ‘There probably is no Aliens’.

    But it is only a probability….

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