FW: What Creation lacks

From: Howard J. Van Till (hvantill@novagate.com)
Date: Mon Oct 29 2001 - 19:31:04 EST

  • Next message: Moorad Alexanian: "RE: Random thoughts"

    Following is a note I received from a biologist friend who is not on the
    listserve but has followed some of our recent discussion on the archives. I
    post it with his permission.

    Howard Van Till

    *************************

    I have followed the discussions on evolution on this site on and off for
    several years now. Now seems like an appropriate time to comment on two
    recent discussions that, to me, seem to be related---what does creation
    lack and the universality of the genetic code.

    Evidence suggests that the genetic code is (at least at the level of
    the first two bases) a real code. That is, you could encode the same
    message in many different ways depending on how the (presumably random)
    assignments are made in the code. In the actual genetic code UUU is
    assigned Phe, CCC is assigned Pro, AAA is assigned Lys, etc. I believe the
    evidence indicates that you could construct any organism using an entirely
    different code: for example, UUU could be Lys, AAA could be assigned Pro,
    etc. In an actual code there is no design in assigning the various
    relationships in the code. In cryptography the code for Day 1 has no
    connection with the code for Day 2 or the code for Day 3 and so on.

    We do not find significant differences in the genetic code for different
    organisms in life on this planet. The code that a mouse employs is just
    like its parents because the mouse inherits its genes and its translation
    mechanisms for the code from its parents. If there was a super genetic
    engineer, such a person could presumably make a mouse virtually identical
    to the mouse we see today using a genetic code entirely unrelated to the
    actual genetic code we find in organisms today. But mice have essentially
    the same code as humans and as trees and as fruit flies and as mushrooms,
    and as bacteria. Why is this so? If they were unrelated to each other
    there would be no reason for them to have this genetic code similarity. The
    fact that they are same is evidence for evolution--inheritance of the
    genetic code from a common ancestor. It is probably the strongest evidence
    that links bacteria to fungi to plants to animals»-that is why it is cited
    so often. Evidence of similar structures in anatomy and for similar
    biochemical pathways that are cited as evidence for a common ancestor are
    dismissed by antievolutionists as resulting from common design. (I
    personally find this a weak argument.) But with the genetic code this
    common design argument doesn't work. It is invalid because the assignment
    of codons to certain amino acids isn't designed. The genetic code
    assignments would be an obvious place for an intelligent designer to insert
    evidence for discontinuities in the history of life. (The Discovery
    Institute itself endorses this concept and in fact makes this argument, and
    DeHaan proposes something like it could exist in a recent post: "I think
    the stages are not hard to discern--prebiotic, unicellular life on earth;
    complex metazoan life, sentient life in the image of God.") Thus, if an
    intelligent designer wished to provide evidence that bacteria were
    different than complex multicellular organisms, that designer could use two
    entirely different genetic codes to construct such organisms. An
    evolutionist would be hardpressed to explain that by common ancestry. But
    different genetic codes are not the case here on Earth however; bacteria
    and humans have the same genetic code. (If a unicellular organism is found
    deep in the earth and it has an entirely different code than the one we
    have found in all organisms so far, I am quite confident few, if any,
    biologists will suggest that this new organism would have a common ancestor
    with all the organisms we know today.)

    So is the genetic code universal? The answer is no. Certain ciliates and
    some mitochondrial DNA have slightly different codon assignments involving
    the STOP codons, the Met codon, the Arg, codons, and a few others.
    However, the differences appear in only a few codons and there is no doubt
    that all the variants are all very similar to the so-called universal
    genetic code. The genetic code makes 64 assignments of codons to amino
    acids»either most or all of the time ( I haven't researched this
    thoroughly) only 1 to 4 of these 64 codons vary from organism to organism,
    the rest remaining unchanged.

    Why aren't all the genetic codes exactly the same? The Discovery Institute
    discussion found on one of the links in a post about two weeks ago on this
    list indicates that these differences are the work of an intelligent
    designer who is providing us with evidence of discontinuities in the
    history of life. According to the Discovery Institute, the reason ciliates
    have a different code is because they were formed separately in some manner
    from the rest of the organisms. They could not have developed from a common
    ancestor because their genetic code is different. Their proposal is that
    the designer is sending us a message of a discontinuity here. The
    evolutionary view is that the genetic code has evolved at a few sites
    (evident in mitochondria and ciliates), but has remained almost unchanged
    over billions of years. On October 18 and on additional posts on this list
    David Campbell provided some ideas to how this evolution might have
    happened. Also, I would add, there are known suppressor mutations that can
    be isolated today in bacteria where a codon is actually read differently
    due to a mutation in the tRNA. These are sick bacteria but they do survive
    in the lab.

    So I see this as a straightforward question: Why is there is a near
    universal genetic code with slight variations? It is not common design, it
    is not even the common use of the same code for everything, since there are
    these variations.

    We have three possible answers, I think:
    (1) The code evolved from a common ancestor since it appears in all life
    today
    (2) The intelligent designer made the different codes to show us
    discontinuities, but did not chose to make the variants obviously different
    at all 64 codons, but just a few at most.
    (3) It is necessary for a ciliate or a mitochondrion to have the particular
    code it does in order to function as it does.

    I don't think there is any evidence for (3). I find (2) to be unacceptable
    because that is counter what I believe an intelligent designer would do if
    that designer was intelligent. An intelligent designer would not make only
    slight variations to keep us guessing about an evolutionary possibility.
    I find (1) to be plausible.

    In summary, I think the near universal genetic code with its small
    variations poses significant problems for the intelligent design
    and the discontinuous positions.

    Al Koop

    koopa@gvsu.edu

    Department of Biology
    Grand Valley State University
    Allendale, MI 49501



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