Home » Intelligent Design, Irreducible Complexity, Science » One step at a time: Motor molecules use random walks to make deliveries in living cells

One step at a time: Motor molecules use random walks to make deliveries in living cells

Physorg.com – July 21st, 2009

Cells rely on tiny molecular motors to deliver cargo, such as mRNA and organelles, within the cell. The critical nature of this transport system is evidenced by the fact that disruption of motors by genetic defects leads to fatal diseases in humans. Although investigators have isolated these motor to study their function in a controlled environment outside the cell, it has been difficult for researchers to follow these fascinating molecular transporters in their natural environment, the living cell.

Now, two articles published by Cell Press in , make use of incredibly tiny, glowing “quantum dots” to track the miniscule motions of myosin V in living cells. Interestingly, both research groups independently report that myosin V molecules carry their quantum dot cargo either in a straight line or in a manner akin to a drunken walk.

Myosin V is a motor molecule that “walks” in a fashion similar to humans by stepping along actin filament tracks that are assembled in a dense, criss-crossing network inside the cell. A critical feature of these motors is their ability to walk long distances without falling off their tracks. However, this has never been observed within cells. Through the binding of quantum dots directly to a single myosin V molecule, both investigative teams used sophisticated microscopes and sensitive cameras to witness the 72 nanometer strides (equivalent to 1 millionth of an inch) taken by these motors for the first time in cells.

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Here is my favorite line: “Cargo delivery in cells can’t totally be a random process, therefore, using the approach described here we can characterize how motors and cargo link up and understand the engineering design principles Mother Nature uses to guarantee efficient and effective delivery of cargo within cells,” offers Dr. Warshaw.   [italics mine]

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38 Responses to One step at a time: Motor molecules use random walks to make deliveries in living cells

  1. Mario,

    Interesting research. And I add this sentence just above your quote…

    “Their findings, published in the July 22nd 2009 issue of the journal, suggested that myosin V’s apparent drunken walk is in fact the motor taking turns at almost every intersection it encounters along the dense and randomly oriented intracellular actin highway.

    So, it is advancing through turns along the highway. The “motor” is doing this. How does it know where to go? What gives it direction to its final destination?

    I’m wondering if this is not random oriented highway, but a sequence of highly regulated turns to the final destination area for cargo exchange.

    Good to know “mother nature is such a good engineer. That totally blows my image of her:

    Mother Nature – Tree Lover… Magical Momma

    I never thought of her as an engineer, hmmmm…. in fact, I kinda thought she was a Hippy at heart… smoke a little mary jane and tune out, turn on and dig nature man.

    Funny how the actual discovery of this has nothing to do with evolution at all, just science figuring out out how things work at the nano-level, where nano-engineers may one day learn how the lattice guides the “motors” turns on the highway of intracellular travel.

    I wonder if there are not guiding lines like we have on our highways with specific lanes that the motors stay in due to weak atomic forces.

    It is very interesting because the motor must first take a step, then release or be released and take another step. So, maybe it is a work of repelling(forcing the step away from certain matrices) as much as attraction to other matrix positions. But then, how does the release mechamism work?

    I’m curious to read both papers.

  2. Truly amazing finding. But alas now mother nature is the designer/engineer in their eyes.

    Here is a video on how myosin activates each “step”:

    myosin
    http://www.youtube.com/watch?v=vJ9ffKeUCvE

  3. It strikes me as cheap to exploit what is clearly a metaphorical reference to “design.”

    I also don’t see how this article supports “intelligent design.” It simply describes a particular aspect of cell function.

  4. Pendragon,

    It also strikes me as extremely disingenuous to continually deny the white elephant of design in the room. There is absolutely nada that is random or undirected in anything that happens in the cell. It reeks of design.

    It is irrational to declare the word design to be a metaphor to explain the supposed ‘appearance’ of design.
    No, there’s no metaphor being used here.

    ….just another hole in the wall.

  5. Pendragon, is your head comfortable in all that sand?

    Metaphor? No, design just happens to be the most succinct and accurate description of empirically and repeatedly observed phenomenon. But no worries, mate; hand-waving and a nice sandy spot to lay one’s head does wonders when one wishes to avoid the blatantly obvious.

  6. Clearly the structure and operation of a cell conform to its function. So in that sense what happens in a cell is certainly not random.

    But I still don’t see what that has to do with the issue of evolution versus design. Why must lack of randomness necessarily imply design?

    I wouldn’t say I have my head in the sand. I am here reading this blog, aren’t I? But it seems that some of you are saying that the existence of a designer is intuitively obvious, and it doesn’t seem obvious to me at all. Besides doesn’t that just move the problem up a level? Aren’t we then left with questions of the origins of the designer, not to mention a question as to the physical mechanism by which the designer created life and developed the species?

  7. “No man-made program comes close to the technical brilliance of even Mycoplasmal genetic algorithms. Mycoplasmas are the simplest known organism with the smallest known genome, to date. How was its genome and other living organisms’ genomes programmed?” – David L. Abel and Jack T. Trevors, “Three Subsets of Sequence Complexity and Their Relevance to Biopolymeric Information,” Theoretical Biology & Medical Modelling, Vol. 2, 11 August 2005, page 8

    Ben Stein – EXPELLED – The Complexity of the Cell – video
    http://www.youtube.com/watch?v=Yibucli2drc

    “We have always underestimated cells. Undoubtedly we still do today….We can walk and we can talk because the chemistry that makes life possible is much more elaborate and sophisticated than anything we students had ever considered…Instead of a cell dominated by randomly colliding individual protein molecules. we now know that nearly every major process in a cell is carried out by assemblies of 10 or more protein molecules. And, as it carries out its biological functions, each of these protein assemblies interacts with several other large complexes of proteins. Indeed, the entire cell can be viewed as a factory that contains an elaborate network of interlocking assembly lines, each which is composed of a set of large protein machines.” Bruce Alberts: Former President, National Academy of Sciences; The Cell as a Collection of Protein Machines

    “Each cell with genetic information, from bacteria to man, consists of artificial languages and their decoding systems, memory banks for information storage and retrieval, elegant control systems regulating the automated assembly of parts and components, error fail-safe and proof-reading devices utilized for quality control, assembly processes involving the principle of prefabrication and modular construction and a capacity not equaled in any of our most advanced machines, for it would be capable of replicating its entire structure within a matter of a few hours” Geneticist Michael Denton PhD.

    “… no operation performed by a computer can create new information.”
    Douglas G. Robertson, “Algorithmic Information Theory, Free Will and the Turing Test,” Complexity, Vol.3, #3 Jan/Feb 1999, pp. 25-34. The Evolutionary Informatics Lab:

    Stephen C. Meyer – Signature In The Cell:
    “DNA functions like a software program,” “We know from experience that software comes from programmers. Information–whether inscribed in hieroglyphics, written in a book or encoded in a radio signal–always arises from an intelligent source. So the discovery of digital code in DNA provides evidence that the information in DNA also had an intelligent source.”
    http://www.evolutionnews.org/2.....ligen.html

  8. Before someone brings up evolutionary algorithms:
    EV Ware: Dissection of a Digital Organism:
    Ev purports to show “how life gains information.” Specifically “that biological information… can rapidly appear in genetic control systems subjected to replication, mutation and selection.” [Yet] It is the active information introduced by the computer programmer and not the evolutionary program that reduced the difficulty of the problem to a manageable level.
    http://www.evoinfo.org/Resources/EvWare/index.html

    Another quote:

    “The manuals needed for building the entire space shuttle and all its components and all its support systems would be truly enormous! Yet the specified complexity (information) of even the simplest form of life – a bacterium – is arguably as great as that of the space shuttle.”
    J.C. Sanford – Geneticist

    Inner Life Of A Cell – A small glimpse at the complexity of a cell – video
    http://multimedia.mcb.harvard.edu/

  9. Look, I am not overly familiar with the ins and outs of the design vs. evolution “controversy” (though I do know enough to know that it is not actually controversial among scientists). I don’t pretend to be an expert. But after lurking on this site for a while, I find myself frustrated with the constant exclamations to the effect that “It’s so obvious theere is a designer! Any 9-year-old could see it!”

    It seems to me, bornagain, that you are just quoting a number of people observing that life is extremely complex, more complex than what we humans are capable of designing. If anything, this seems to me to militate the notion of some kind of consciousness deliberately designing life and its processes. You also have quotations from people claiming or implying that, if I understand correctly, new genetic information cannot arise without design.

    I am not sure why not. Obviously, the information or its raw materials had to come from somewhere at some point. The information that allows the designer to function has to have come from somewhere.

  10. In addition to the formal proof of the Law of Conservation of Information by Dembski and Marks, which falsifies the theoretical foundation of unguided evolution, “pure transcendent information” is now shown to “eternally exist” by the controlled violation of the first law of thermodynamics in quantum teleportation experiments. (i.e. it is shown that all transcendent information which can possibly exist, for all possible physical events, past, present, and future, already does exist.)

    Conservation Of Transcendent Information – 2007 – video
    http://www.youtube.com/watch?v=5Hm4lh81r6M

    Light and Quantum Mechanics Reveal The Information Basis Of Our Universe – video
    http://www.youtube.com/watch?v=F-0Yrbs7rbo

    How Teleportation Will Work -
    Excerpt: In 1993, the idea of teleportation moved out of the realm of science fiction and into the world of theoretical possibility. It was then that physicist Charles Bennett and a team of researchers at IBM confirmed that quantum teleportation was possible, but only if the original object being teleported was destroyed. — As predicted, the original photon no longer existed once the replica was made.
    http://in.geocities.com/info_aruni/tele.htm

    As well, the following video shows quantum teleportation breakthroughs have shed even more light on exactly what, or more precisely on exactly Whom, has created this universe:

    Scientific Evidence For God Creating The Universe – 2008 – video
    http://www.youtube.com/watch?v=JQhO906v0VM

    Explaining Information Transfer in Quantum Teleportation: Armond Duwell †‡ University of Pittsburgh
    Excerpt: In contrast to a classical bit, the description of a qubit requires an infinite amount of information. The amount of information is infinite because two real numbers are required in the expansion of the state vector of a two state quantum system (Jozsa 1997, 1) — Concept 2. is used by Bennett, et al. Recall that they infer that since an infinite amount of information is required to specify a qubit, an infinite amount of information must be transferred to teleport.

    Single photons to soak up data:
    Excerpt: the orbital angular momentum of a photon can take on an infinite number of values. Since a photon can also exist in a superposition of these states, it could – in principle – be encoded with an infinite amount of information.

    Ultra-Dense Optical Storage — on One Photon
    Excerpt: Researchers at the University of Rochester have made an optics breakthrough that allows them to encode an entire image’s worth of data into a photon, slow the image down for storage, and then retrieve the image intact.

    This following experiment clearly shows information is not a “emergent property” of any solid material basis as is dogmatically asserted by some materialists:

    Converting Quantum Bits: Physicists Transfer Information Between Matter and Light
    Excerpt: A team of physicists at the Georgia Institute of Technology has taken a significant step toward the development of quantum communications systems by successfully transferring quantum information from two different groups of atoms onto a single photon.
    http://gtresearchnews.gatech.e.....mtrans.htm

  11. Reflection on the quantum teleportation experiment:

    That a photon would actually be destroyed upon the teleportation of its “infinite” information to another photon is a direct controlled violation of the first law of thermodynamics. Thus, this is a direct empirical validation for the primary tenet of the Law of Conservation of Information (i.e. information cannot be created or destroyed). This conclusion is warranted because information exercises direct dominion of energy, which cannot be created or destroyed by any known material means, yet a photon of energy is destroyed by this transcendent means. Thus, this experiment provides a direct line of logic that transcendent information cannot be created or destroyed. Clearly anything that exercises dominion of the fundamental entity of this physical universe, energy, must of necessity possess the same, as well as greater, qualities. i.e. All information that can exist, for all past, present and future events of energy, already must exist. Another line of evidence, corroborating the primary tenet of the Law of Conservation of Information, is the required mathematical definition for infinite information needed to correctly specify the reality of a photon qubit (Armond Duwell).

  12. Further reflections on the “infinite transcendent information” framework:

    Mass becomes infinite at the speed of light, thus mass will never go the speed of light. As well, distance in direction of travel will shrink to zero for mass at the speed of light (i.e. the mass would disappear from our sight if it could go the speed of light.). For us to hypothetically travel at the speed of light, in this universe, only gets us to first base as far as quantum teleportation is concerned. That is to say, traveling at the speed of light only gets us to the place where time, as we understand it, comes to complete stop for light, i.e. gets us to the eternal, “past and future folding into now”, framework/dimension of time. This “eternal” inference for light is warranted because light is not “frozen within time” yet it is shown that time does not pass for light.

    “I’ve just developed a new theory of eternity.”
    Albert Einstein

    Also, hypothetically traveling at the speed of light in this universe would be instantaneous travel for the person going at the speed of light. This is because time does not pass for them, but, and this is a big but; this “timeless” travel is still not instantaneous and transcendent to our temporal framework/dimension of time, i.e. Speed of light travel, to our temporal frame of reference, is still not completely transcendent of our framework since light appears to take time to travel from our perspective. In information teleportation the “time not passing”, eternal, framework is not only achieved in the speed of light framework/dimension, but also in our temporal framework/dimension. That is to say, the instantaneous teleportation/travel of information is instantaneous to both the temporal and speed of light frameworks/dimensions, not just the speed of light framework. Information teleportation/travel is not limited by time, nor space, in any way, shape or form, in any frame of reference, as light is seemingly limited to us. Thus “pure information” is shown to be timeless (eternal) and completely transcendent of all material frameworks/dimensions. Moreover, concluding from all lines of evidence we have now examined; transcendent, eternal, infinite information is indeed real and the framework in which it inhabits is the primary reality (highest dimension) that can exist, (in so far as our limited perception of a primary reality, highest dimension, can be discerned). Logic also dictates “a decision” must have been made, by the “transcendent, eternal, infinite information” from the primary timeless reality it inhabits, in order to purposely create a temporal reality with highly specified, irreducible complex, parameters from infinite possibilities in the proper sequential order. Thus this infinite transcendent information, which is the primary reality of our reality, is shown to be alive. The restriction imposed by our physical limitations of us ever accessing complete infinite information to our temporal physical framework/dimension does not detract, in any way, from the primacy and dominion of the infinite, eternal, transcendent, information framework/dimension that is now established by the quantum teleportation experiment as the primary reality of our reality. Of note: All of this evidence meshes extremely well with the theistic postulation of God being infinite and perfect in knowledge.

    “An illusion can never go faster than the speed limit of reality”
    Akiane – Child Prodigy – Artwork homepage – music video

    As a side light to this, leading quantum physicist Anton Zeilinger has followed in John Archibald Wheeler’s footsteps (1911-2008) by insisting reality, at its most foundational level, is “information”.

    Why the Quantum? It from Bit? A Participatory Universe?
    Excerpt: In conclusion, it may very well be said that information is the irreducible kernel from which everything else flows. Thence the question why nature appears quantized is simply a consequence of the fact that information itself is quantized by necessity. It might even be fair to observe that the concept that information is fundamental is very old knowledge of humanity, witness for example the beginning of gospel according to John: “In the beginning was the Word.”
    Anton Zeilinger – a leading expert in quantum teleportation:
    http://www.metanexus.net/magaz.....fault.aspx

  13. Yes, Pendragon, there are many I.D. supporters here, obviously. What you observe is to be expected to a degree. If you are really looking for information and understanding, stick around. I’ve gotta get to bed myself, but many here can answer your curiosities. I think bornagain77 is in his own little world for the moment; don’t feel he’s ignoring you… at least I don’t think he is :)

  14. Brent,
    He wanted to know where the information was coming from so I showed him.,,,Maybe with a bit to much detail, but the science is solid.

  15. I will certainly read through some of this stuff (as well the on-line refutations), but you will have to excuse me if I remain skeptical. I give quite a bit of weight to the fact that the scientific establishment has overwhelmingly rejected ID as science. You may claim that I am blindly following authority, but to me, the scientific process and the process of peer review carries a lot of weight. ID doesn’t seem to be doing too well in that arena so far and, frankly, as a member of the public, that matters to me.

    P.S. Who is this “he” you speak of? It is actually “Ms. Pendragon.”

  16. Hello Ms Pendragon,

    I am glad to see that you are at least open to discussion about this controversial topic. I would recommend that you read some of the ID books that are out (online articles tend to have a pretty restricted scope). Of course, I would also encourage you to read the criticisms and their rebuttals. :)

    The history of science is pretty straightforward and obviously relentlessly seeking to finish off “design” and establish materialism.

    If you are going to appeal to authority, a brief look into the history of science will show that “design” has never left its vocabulary. Scientists must always resort to “design” language because it is inevitable to do so. Keep in mind that nature has been around much longer than science and that language (i.e., descriptions) has little to do with the functional and specified complexity found in living systems. We can call it a motor or well-organized feces, but the point is that we can distinguish teleology from non-teleology and this is something that scientists cannot seem to escape.

    In the meantime, good luck in your search. ;)

  17. Pendragon,

    The argument for design is one of likelihood. When you observe complex things interacting with each other for a specific purpose, you have to ask how that arose. In our world one would not think twice and would assign it to some clever person or persons and never to a fortuitous accumulation of materials. Now in life, we see similar things but no individual or person who could have done it because it happened very long ago so we have to say maybe it did arise naturally because there was an awful lot of time but then we look at nature and see nothing like this organized complexity except in life. And ask yourself why just this one thing. And this one thing even has a computer like program that guides its operation.

    Do we automatically say it must have risen naturally or could there have been an intelligence that we are unaware of that caused it. If we had some knowledge of an ancient intelligence that existed at the time of earth’s formation from some other location no one would think twice about the authors or designers of life. But we don’t. So what do we do. Say there never was any such intelligence and some incredibly string of events led to this fantastic organized complexity or do we come to a different conclusion and say nature cannot do this alone so there must have been some other intelligence even if we have no physical evidence for it.

    Either way has no hard proof. So which is it. The almost impossible incredibly lucky string of highly unusual events or the existence of an intelligence. Take your pick. Or do you take the position that it could be either one and it is currently a mystery. If you are the latter then you are a supporter of ID. If you take the position that life must have a natural origin and there is absolutely no possibility that an intelligence existed then you are a naturalist and anti ID. You are one of those who are absolute about this controversy and thus, allows no dissent from the chosen dogma.

  18. bornagain77,

    Alright. I enjoy what you post quite much, but if I don’t have time I almost invariably skip or very quickly skim your posts. I come back to them and read and follow links when I can. Since I only skimmed your posts and I didn’t notice any reference directly to pendragon I thought you were just kinda focused on something else.

  19. Jerry,

    Thank you for your lucid explanation. I did sort of read between the lines of bornagain’s cut-and-paste to glean that that was what he was getting at.

    I think that, on a purely intuitive level, the likelihood argument has a lot of appeal. But when you consider the time span we are talking about and the sheer number of creatures who have lived and died — and species that have gone extinct — I don’t automatically buy the idea that it would be “unlikely” for complex species such as our own to have developed.

    It also seems that “intelligent design” has just as much if not more of a “likelihood problem.” The intelligence guiding the process must have also come from somewhere, no? It seems to me far more “likely” that life would emerge in gradual baby steps over a vast expanse of time, than that a brilliant, all-powerful consciousness just happened to poof into existence and start creating things. The chances of the designer simply coming into being seem far more astronomical than any of the gradual changes over time posited by people who accept evolution.

    I suppose I am a “naturalist,” though I reject the false dichotomy you propose. I reject the dichotomy you propose because I don’t see an incredibly lucky string of highly unusual events — I see countless unsuccessful, unlucky animals and species that couldn’t make the grade in the game of survival, suffered, and died out.

    I also accept that it is possible that there is some sort of cosmic intelligence that we are unable to understand that is somehow in some unknowable way directing the development of life on earth. But this proposition seems wholly irrelevant to anything with which biology should concern itself. How on earth does such a possibility answer any questions about the physical process of how life came to be or how the various species came to be?

    I am a naturalist in the sense that I think the biological sciences should concern itself with natural explanations. Positing some sort of designer answers no questions as to how physically life came into being or how our or any other species came into being. It is a basically useless construct in terms of answering questions about how life works on a physical level.

    Once you start taking biology out of the realm of the material or natural, it is no longer biology, but something else altogether.

  20. I think revisiting Haldane’s dilemma regarding the time span allowed for such complexity to arise is worth revisiting with a dedicated thread. More people need to be aware and consider such things.

  21. Mr PaulN,

    Shouldn’t software like Mendel’s Accountant and Gregor’s Bookkeeper be able to test the relevance of the ‘Haldane’s Dilemma’ argument experimentally? I think concrete experimental results will provide more conclusive arguments.

  22. 22

    PaulN,

    What, exactly, does Haldane’s Dilemma have to do with limits on the development of complexity?

  23. Dave Wisker,

    The potential for natural processes to develop the complexity we see in life is an entirely different argument, and one that KairosFocus has well quantified.

    The time span alone as an independent factor according to Haldane’s Dilemma even when given conservative numbers on the amount of generations required for a beneficial mutation to become fixed in a population, become too overwhelming once you begin to consider how many beneficial mutations would be required for man to split from an ape-like ancestor.

    Nakashima,

    As far as Mendel’s accountant, I think it’s something definitely worth looking further into as I’ve never considered it myself. As far as I know, the program is free to download and try out.

  24. 24

    PaulN,

    How many beneficial gene substutions are required for man to split from an ape-like ancestor?

  25. I believe that burden is on the person proposing the positive isn’t it?

  26. Not trying to pass the buck, but my best guess would be alot. Do you know of any Darwinian researchers who have given even so much as a ballpark estimate of the number required? They’re the one’s proposing that we evolved from an ape-like ancestor, so the burden is on them.

  27. Also, a conservative estimate according to Haldane’s dilemma would be about 300 generations for each beneficial single-nucleotide mutation to become fixed in a population. You provide me with a general estimate of required mutations for the evolution of man from his ape-like ancestors and we can move forward from there.

  28. Isn’t the punchline of this joke that ReMine insisted that it had to be less than 1,667 and it really turned out to be 154?

  29. 29

    PaulN,

    Not trying to pass the buck, but my best guess would be alot. Do you know of any Darwinian researchers who have given even so much as a ballpark estimate of the number required? They’re the one’s proposing that we evolved from an ape-like ancestor, so the burden is on them

    Well, you are passing the buck, actually. On what do you base your best guess?

  30. 30

    PaulN,

    You provide me with a general estimate of required mutations for the evolution of man from his ape-like ancestors and we can move forward from there.

    Paul, I’m not the one stating that the number of required beneficial substitutions should be “a lot”. You are. The burden’s is squarely on you, dude.

  31. Dave dude, is it not true that your side proposes it is ‘possible’ for fortuitous mutations, becoming fixed in a population, to build up a genome?

    Forget PaulN’s cloudy ‘alot’ declaration. Give us the hard numbers and show us how science is ‘really’ done.

    I mean really, somebody’s got to put ID in its place and fast.

  32. 32

    Hi Oramus,
    ‘Dave dude, is it not true that your side proposes it is ‘possible’ for fortuitous mutations, becoming fixed in a population, to build up a genome?
    We not only proposed it, we have observed it. I suggest you peruse the classic experiments Dobzhansky did on Drosophila chromosome inversions. Surely you are aware of them?
    Forget PaulN’s cloudy ‘alot’ declaration.
    Why should I?
    Give us the hard numbers and show us how science is ‘really’ done.
    You seem to assume that I think evolutionary theory can predict the number of beneficial gene substitutions required to explain the human chimpanzee split. Why would you think that?
    I mean really, somebody’s got to put ID in its place and fast.
    Listen, mate. This part of the thread was between PaulN and me. He made a declaration, whereas I only asked questions. The burden remains on him to either produce the reasons for his guess, or simply admit he had no good reason to make the guess in the first place. It’s really that simple.

  33. Dave,

    No, I am not assuming anything.

    It is ND that assumes the probability of beneficial mutations creating and modifying organisms.

    We are simply waiting for the empirical evidence that such is in fact the case.

    Your diversionary ‘questions’ cannot hide the white elephant in the room.

    One thing is for sure, ND sure does play mean pinball.

  34. Non-random evolution?… Engineering design principles?
    All by “Mother Nature”?!…

    I believe we should propose Mother Nature for (at least) one Nobel Prize for excellent scientific work and great engineering design(s)!
    Anyone else to support me on this?… :)

  35. 35

    Oramus,

    My so-called ‘diversionary’ questions specifically addressed another contributors statements. If any diversion is gong on, it is coming from you. I understand how you would want everyone to “forget about” PaulN’s statements–especially if the answer to my questions shows there is no basis behind expecting a large number of beneficial gene substitutions to explain the human/chimpansee divergence. I just want it made clear who is doing the diverting here.

  36. 36

    Mr Nakashima,

    Isn’t the punchline of this joke that ReMine insisted that it had to be less than 1,667 and it really turned out to be 154?

    As I recall, ReMine thinks it would require far more than 1667 beneficial substitutions.

    As for the 154 figure, that was the number of genes found under positive selection in the human lineage, but only 14,000 genes were examined. It’s still far lower than some ID proponents would like to hear.

  37. Mr Wisker,

    Yes, what I meant was that ReMine felt that Haldane’s Dilemma put an upper limit on the number of beneficial substitutions at 1667, though he himself felt many more would be necessary. Sorry if I was unclear.

    So is it wrong to compare 1667 and 154? Are they really apples and oranges?

  38. 38

    Mr Nakashima,

    That’s what I thought you meant, I just wanted to make sure.

    So is it wrong to compare 1667 and 154? Are they really apples and oranges?

    No, I think its an eminently reasonable thing to do here. I don’t know of any reason to think that there is a huge number of genes showing evidence of positive selection in the remaining genes that haven’t been examined yet. What amuses me more is this demand from our ID friends that we come up with some estimate of how many beneficial substitutions are required to explain the human/chimp divergence (or, more properly, the the number required to explain the history of the human lineage since the split). Such a prediction would require an extremely detailed picture of the paleoecology of the time from the split to the present, because, as I’m sure you know, how we determine mutations as being beneficial or not depends heavily on the ecological context in which they find themselves. Not only that, we would also have to know how the populations were structured in order to consider the effects of stochastic effects such as drift effecting substitution times. And that is just two variables among many more that we just don’t have enough of a grasp to make a prediction.

    Given the above, I don’t see how our ID friends can so confidently say that a large number (or at least more than the Haldane ‘limit’ of 1667) are required. I know, from an evolutionary perspective, we don’t have anywhere near enough knowledge to make any kind of prediction.

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