Sunday, September 24, 2006

The anaphase promoting complex/cyclosome: a machine designed to destroy

The anaphase promoting complex/ cyclosome: a machine designed to destroy, Nature Reviews Molecular Cell Biology, 7, 644-656, September 2006, Jan-Michael Peters ...

[Graphic: The Anaphase Promoting Complex/Cyclosome (APC/C), Research Institute of Molecular Pathology (IMP)]

The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase that has essential functions in and outside the eukaryotic cell cycle. It is the most complex molecular machine that is known to catalyse ubiquitylation reactions, and it contains more than a dozen subunits that assemble into a large 1.5-MDa complex. Recent discoveries have revealed an unexpected multitude of mechanisms that control APC/C activity, and have provided a first insight into how this unusual ubiquitin ligase recognizes its substrates. ... Note the words, " a machine designed to ..." and "has essential functions in and outside the eukaryotic cell cycle" (my emphasis)!

Sounds like yet another "highly specified, irreducibly complex system" which "Attempts to explain the evolution of ... by a gradualistic route" will continue to be "incoherent" due to "a choking complexity" which "strangles all such attempts":

"Attempts to explain the evolution of highly specified, irreducibly complex systems either mousetraps or cilia or blood clotting-by a gradualistic route have so far been incoherent, as we have seen in previous chapters. No scientific journal will publish patently incoherent papers, so no studies asking detailed questions of molecular evolution are to be found. Calvin and Hobbes stories can sometimes be spun by ignoring critical details, as Russell Doolittle did when imagining the evolution of blood clotting, but even such superficial attempts are rare. In fact, evolutionary explanations even of systems that do not appear to be irreducibly complex, such as specific metabolic pathways, are missing from the literature. The reason for this appears to be similar to the reason for the failure to explain the origin of life: a choking complexity strangles all such attempts." (Behe, M.J., "Darwin's Black Box: The Biochemical Challenge to Evolution," Free Press: New York NY, 1996, p.177)

The late molecular biologist Francis Crick was no doubt thinking of such molecular machines when he wrote, "Biologists must constantly keep in mind that what they see was not designed, but rather evolved" (my emphasis):

"What is found in biology is mechanisms, mechanisms built with chemical components and that are often modified by other, later, mechanisms added to the earlier ones. ... Biologists must constantly keep in mind that what they see was not designed, but rather evolved." (Crick, F.H.C., "What Mad Pursuit: A Personal View of Scientific Discovery," [1988], Penguin Books: London, 1990, reprint, p.138)

The problem for molecular biologists however is that, as exemplified with this subject line, they cannot help but use the language of intelligent design, because, as Richard Dawkins admitted, living things "overwhelmingly impress us with the appearance of design as if by a master watchmaker" (my emphasis):

"Natural selection is the blind watchmaker, blind because it does not see ahead, does not plan consequences, has no purpose in view. Yet the living results of natural selection overwhelmingly impress us with the appearance of design as if by a master watchmaker, impress us with the illusion of design and planning. .. We may say that a living body or organ is well designed if it has attributes that an intelligent and knowledgeable engineer might have built into it in order to achieve some sensible purpose, such as flying, swimming, seeing, eating, reproducing, or more generally promoting the survival and replication of the organism's genes. It is not necessary, to suppose that the design of a body-or organ is the best that an engineer could conceive of. ... But any engineer can recognize an object that has been designed, even poorly designed, for a purpose, and he can usually work out what that-purpose is just by looking at the structure of the object." (Dawkins, R., "The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design," W.W Norton & Co: New York NY, 1986, p.21).

But unfortunately for Dawkins' "blind watchmaker" explanation of this particular molecular machine is that it is an essential component of anaphase, i.e.:

"Anaphase ... the stage of meiosis or mitosis when chromosomes separate in a eukaryotic cell. Each chromatid moves to opposite poles of the cell, the opposite ends of the mitotic spindle, near the microtubule organizing centers ..."

And as the late Fred Hoyle pointed out, "the theory of evolution by natural selection" (i.e. the "blind watchmaker") can only "be made to work" with "the sophisticated model of" eukaryotic "sexual reproduction accompanied by crossover":

"Two points of principle are worth emphasis. The first is that the usually supposed logical inevitability of the theory of evolution by natural selection is quite incorrect. There is no inevitability, just the reverse. It is only when the present asexual model is changed to the sophisticated model of sexual reproduction accompanied by crossover that the theory can be made to work, even in the limited degree to be discussed .... This presents an insuperable problem for the notion that life arose out of an abiological organic soup through the development of a primitive replicating system. A primitive replicating system could not have copied itself with anything like the fidelity of present-day systems .... With only poor copying fidelity, a primitive system could carry little genetic information without λ [the mutation rate] becoming unbearably large, and how a primitive system could then improve its fidelity and also evolve into a sexual system with crossover beggars the imagination." (Hoyle, F., "Mathematics of Evolution," [1987], Acorn Enterprises: Memphis TN, 1999, p.20)

that anaphase is a prerequisite of!

So, it sounds like yet another chicken-and-egg dilemma for "blind watchmaker" Darwinism.

But of course Dawkins' (and Crick's) atheist personal philosophy prevents them from drawing the obvious conclusion, that the reason living things "overwhelmingly impress us with the appearance of design as if by a master watchmaker" such that "Biologists must constantly keep in mind that what they see was not designed" is because they were "designed ... by a master watchmaker"!

Stephen E. Jones, BSc (Biol).
Genesis 3:6-7. 6When the woman saw that the fruit of the tree was good for food and pleasing to the eye, and also desirable for gaining wisdom, she took some and ate it. She also gave some to her husband, who was with her, and he ate it. 7Then the eyes of both of them were opened, and they realized they were naked; so they sewed fig leaves together and made coverings for themselves.