Farrellmedia |
|
|
Reports and commentary on the news, science, and creative ends of the media. Contact: My Most Recent Book MEDIA LOG Blogroll: |
Wednesday, April 29, 2009
The Evolution of Protein Folding: Is a Crisis Brewing for Darwin? Historically speaking, there is a distinction to bear in mind between puzzles that prove a challenge to a scientific theory and puzzles that turn into a crisis. The Michelson-Morley experiment in the late 19th century proved to be a crisis for classical physics. So did black-body radiation. The former led to Einstein's special theory of relativity. The latter to quantum mechanics. Both involved radically new ways of visualizing space and time that could not be avoided if --in the case of Einstein-- symmetry was to be reached between classical mechanics and Maxwell's electrodynamics, and--in the case of Planck-- sense was going to be made of all the observational data on radiation. On the other hand, up to the end of the 19th century, Newtonian physics had weathered many puzzles that required some refinement of the theory only. Darwin's theory has also faced its share of puzzles (and continues to). Before the advent of genetics in the early 20th century, for example, natural selection was looking like something far worse than a puzzle for evolution. Then population genetics grew as a field and the work of specialists such as Simpson, Dobzhansky (to name just a few) established firmer grounds for natural selection. Still, a crisis is what many skeptics of evolution thirst for, and as often happens what you'd like to see can blind you to what is actually there (or not there). Proponents of Intelligent Design think it's the complexity of the bacterial flagellum that cannot be explained in terms of genetic variation and natural selection. I was struck by a comment made a while back related to proteins. It all started with Francis Beckwith's post at What's Wrong with the World on the incompatibility between Aquinas and Intelligent Design. WWWTW blog is self-consciously modeled on Chesterton's classic essay collection of the same name (and in fact I have a first edition American, 1910, soon approaching it's 100th birthday and in very good condition). And while it is encouraging that Aquinas and Intelligent Design don't fit--it remains odd to me that the hostility many academics of Catholic, mainline protestant and Orthodox traditions have for evolution is subtler but not fundamentally different from that of, well, fundamentalists and the more overt intelligent design proponents. Which is to say: an always negative tendency to attack scientists for what they don't know yet. For all the adherence to Aquinas and his arguments from secondary causes, it seems many can't resist falling into the God of the Gaps reasoning implied by the natural theology of Protestant William Paley. (Whatever happened to checking in with Cardinal Newman?) For example, apropos of a quip by Lydia McGrew dismissing the use of computer models for evolution ("Just amazing what you can do when "seeing" computer programs "evolve" rather than dealing with actual biological entities. If that counts as "scientists have shown" I have several bridges to sell them."), fellow What's Wrong With the World blogger (and, I'm green with envy to say, instrument-rated private pilot) Zippy followed up: By this reasoning, evolution is apparently worse than an empty suit, prematurely being celebrated by scientists doing nothing. The assertion here seems to be that no actual progress is being made on what amounts to a major problem for evolutionary biology. Is a crisis in the offing? As we'll see, the answer is no. But it is a challenge, and a fascinating one that, to this layman's eye, looks bound to lead to more fruitful discoveries. "But," he adds, "this is a bit like saying you can never understand the architecture of a church without an atomic resolution model of all the materials and components that make it up. Or that because we cannot model every atom in the atmosphere, we have no understanding of the weather and cannot make useful weather forecasts. While we may not be able to predict the folded structure of a protein from its sequence, let alone of every 100 amino acid protein in protein sequence space, that does not mean we cannot perform experiments or make observations that inform our understanding of early protein evolution." According to Nick Matzke, a researcher at the Huelsenbeck Lab, Center for Evolutionary Genomics at U.C. Berkeley, "the processes that we think produce new genes/proteins etc. are not equivalent to random-assembly-all-at-once-from-scratch... We have duplication, modification, selection, rearrangement, etc. " "Even the very first polypeptides were pretty certainly not assembled all-at-once-from-scratch from a pool of 20+ kinds of amino acids in even proportions, in D- and L-form, as creationists and various beknighted physicists blithely assume. Probably the first time a proto-tRNA grabbed an amino acid and made a short chain, the chain was composed of glycine and few common hydrophobic amino acids and was quite short. Cavalier-Smith (2001) suggests that the original function may have just been a hydrophobic tail for association with a membrane. All of the improbability statistics are irrelevant in this sort of scenario, chirality isn't an issue, etc. " This is in line with the current research, for example, of Professor Andrei N. Lupas, director of the Department of Protein Evolution at the Max-Planck-Institute for Developmental Biology in Tübingen. Accrording to Prof. Lupas, "The problem arises from the fact that random polypeptide chains indeed essentially do not fold (I would estimate the proportion to about 1:1020 for polypeptides in the range between 70 to 120 residues). Clearly abiotic systems cannot produce the starting material for a random exploration of folding space (never mind the problem of passing on the information on anything useful you encountered) and it beggars belief that biotic systems could emerge that produce 99.99999999999999999% trash for an initially barely selectable benefit. " But this is hardly a reason to toss out the principles of evolutionary biology. According to Prof. Lupas: "The solution obviously is to propose that an initial RNA world used peptides for other purposes, in which folding was not an issue, but that it selected for peptides that could become structured upon encountering an RNA scaffold (there is ample evidence that there is a natural affinity between peptides and nucleic acids and that random peptides have a tendency to bind into the grooves, becoming structured through the exclusion of water). The issue then becomes to explain how a set of (non-folding) peptides could yield (folding) polypeptides under natural selection. "In my department at the MPI in Tübingen, we explore the hypothesis that folded proteins indeed arose from this preselected pool of peptides, through amplification, fusion and recombination. By being written into one chain, these peptides preselected for the ability to form secondary structures would have found that in many cases they could now exclude water between each other, without the need for an RNA scaffold. Folding would thus be an emergent property resulting from the increased length and complexity of peptides. If this is true, then we think we should be able to reconstruct this vocabulary of peptides in the same way in which ancient languages such as indo-European have been reconstructed through the comparison of modern languages." Two of Lupas' recent papers are here: On the evolution of protein folds: are similar motifs in different protein folds the result of convergence, insertion, or relics of an ancient peptide world? Lupas AN, Ponting CP, Russell RB.J Struct Biol. 2001 May-Jun;134(2-3):191-203. More than the sum of their parts: on the evolution of proteins from peptides. Söding J, Lupas AN. Bioessays. 2003 Sep;25(9):837-46. Professor Lupas also contributed a chapter to Computational Structural Biology, published last September, which is devoted to the evolution of protein folds. Here's a snippet worth quoting at length from the end of the chapter: Proteins may have originated by the repetition of short peptides, a process that efficiently yields fibrous proteins such as coiled coils and ?-helices.39,40 Repetitive sequences appear to have a higher chance of folding and also more favorable structural properties than nonrepetitive sequences.41,42 The problem of passing on the sequence information, however, remains unsolved. Also, domains seen today do not have fibrous elements at their core; there is a discontinuity in fold complexity between fibers and all other folded domains and fibers are structural, not catalytic elements, whereas the primary role of proteins is catalysis.From the other side of the world, Ian Musgrave, professor at the University of Adelaide in Australia writes, "as others have already said, proteins probably didn't arise from random assembly of 100+ amino acids in one go in the first place. " But they didn't need to. He cites, among others, these two papers: Keefe AD, Szostak JW. Functional proteins from a random-sequence library. Nature. 2001 Apr 5;410(6829):715-8. Link here. J Mol Evol. 2003 Feb;56(2):162-8.Can an arbitrary sequence evolve towards acquiring a biological function? Hayashi Y, Sakata H, Makino Y, Urabe I, Yomo T. (Musgrave: "The answer is yes.") Keefe and Szostak are optimistic about their progress: Our isolation of new functional proteins shows that it should be possible to obtain an unbiased view of the inherent diversity of all possible protein structures, and to determine whether biological proteins represent only a small subset of this diversity. Comparing the sequences of our newly evolved ATP-binding proteins with biological ATP-binding proteins has not revealed any significant similarity; structural data will also be required to reveal whether these proteins, especially the Zn2+ metalloprotein, are similar to those of any biological proteins. According to Musgrave, "a modest fraction [of random polypeptides] (somewhere between 1 in 108 and 1 in 1012) have some sort of selectable function." These are just a few scientists with whom I raised the question. There are many more making the evolution of protein folding the center of their attention. Far from being a black box embarrassment to evolutionary biology, the evolution of protein folding turns out to be a challenge worthwhile to quite a few specialists. So where does that leave the assertion of crisis at the state of protein evolution? To me it seems no different than the discredited irreducible complexity arguments of the ID movement. Because protein folding cannot be fully explained now by the principles of evolutionary biology (i.e, descent with modification by the mechanisms of genetic variation and natural selection), the thinking goes, it must therefore call into question the entire theory. As I mentioned earlier, I understand why this kind of argument is irresistible to fundamentalist evangelicals. But it still surprises me that academics with a clear tradition of appreciation for Aquinas and secondary causes flirt with it. Labels: evolution, intelligent design 13 comments Tuesday, April 28, 2009
A good post by Massimo Pigliucci: Scott — who is an atheist — has repeatedly said that one cannot claim that science requires atheism because atheism is a philosophical position, not a scientific one. She leverages the standard distinction between philosophical and methodological naturalism: if you are a scientist you have to be a methodological naturalist (i.e., assume for operative purposes that nature and natural laws are all that there is); but this doesn’t commit you to the stronger position of philosophical naturalism (i.e., to the claim that there really isn’t anything outside of nature and its laws). Years ago, when I first met Genie Scott, I had a Dawkins-like problem with this. I saw the distinction as sophistic hair splitting, and told her so (she was my guest for one of the annual Darwin Day events at the University of Tennessee). Then I started taking philosophy courses, understood what she was saying, and found it irrefutable. I sent her an email apologizing for my earlier obtusity. 3 comments Monday, April 27, 2009
I've got bad news for Christopher Hitchens It's long been known by booksellers and publishers that the New York Times weekly 'list' has never really been a very accurate tally of what indeed is selling in the U.S. I recommend every once in a while taking a look at USA Today's more accurate listing. It's not encouraging. For the last week on record (4/19/2009), for example, we can note that there is not one science book on the list. Out of 150. On the other hand, it looks like books for Young Readers are pretty much dominating sales everywhere, so we know the younger generation likes to read. (This would be even more encouraging if there were fewer vampire novels--but on the other hand, who am I to complain? I started out sucking down every Star Trek adaptation in print in the 1970s.) That said, I think the world can do without the cynical new craze of Jane Austen novels being re-fitted to accommodate zombies. (I did enjoy the Zombie Survival Guide. That kind of parody I think is completely legit.) Christopher Hitchens may want to rethink boasting about his place on the current New York Times bestseller list. On USA Today, God is Not Great doesn't even rate. Which may be a sign that even 'new' atheism is getting old. 0 comments Friday, April 24, 2009
Hitch:
Complete article. 0 comments Tuesday, April 21, 2009
Brendan O'Neill is ready to stick a spoon down his throat over Susan Boyle. Of course, everyone loves a good show tune. And everyone loves an underdog. But Boylemania has become about so much more than an underdog singing a good show tune. Rather, Ms Boyle has been turned into an SIE (Shared International Experience) whose angelic voice and against-the-odds international fame apparently reveal that feminism is alive and well, beauty is overrated, the recession ain’t that bad, cynicism is dying, and God still loves us. You think I’m exaggerating? Consider the 10 craziest things that have been said over this past week-and-a-half of global Boylebarminess. 0 comments Monday, April 20, 2009
The Drowned Giant British writer J.G. Ballard has passed away at age 78. Mostly known for his novels Crash and Empire of the Sun, both made into mediocre Hollywood films, he was to my mind a better short story writer. His collection The Terminal Beach includes two of my favorite short stories, The Drowned Giant and The Lost Leonardo. The former was about the reaction of a seaport city to the appearance of a dead giant, washed up on the beach one morning. Labels: J. G. Ballard, literature, science fiction 1 comments Friday, April 17, 2009
It being National Poetry Month, there are a couple of things you shouldn't miss: One is that Siris, in addition to being a philosopher for the working day, is an excellent poet. As demonstrated by samples here and here. And that's just the tip of the iceberg. He posts verse often, so if you haven't subscribed to his blog, add him to your blogroll. The other is this site, which I understand from the cracker-jack producers behind it, is still in development phase but promises to build a fairly impressive media library within the next few years. Labels: literature, poetry, verse 1 comments Tuesday, April 14, 2009
0 comments Friday, April 10, 2009
![]() Good Friday We're so used to just repeating texts from the Gospels this time every year, we can forget how much more startling art can be. Imagine what a satellite might have snapped about 1,979 years ago. I've always found this tech art (by the Glue Society), haunting. 0 comments Thursday, April 09, 2009
Stanley Jaki, physicist, priest, author and teacher: 1924 - 2009 One of my favorite historians of science, Fr. Jaki, has passed away, at age 84. After lecturing last week in Rome he went to Spain for further meetings and succumbed to a heart attack.
I have about 20 of his published books, and I reread chunks of them (and highlight them to death) whenever I can. I had the good fortune to hear him lecture at MIT and elsewhere in Cambridge about 15 years ago. He had a marvelous (sometimes biting) sense of humor, and even in the course of just a few lectures I could tell he was not the kind of man to suffer fools gladly. His books are invaluable resources, just for the reference material and bibliographies alone. And no one seriously studying the rise of science in the West can ignore his work, even if (as I would say) the 'mainstream' of history of science scholars does not agree with his views. More here. Labels: history of science, Jaki, science education 2 comments Reality Check I want to follow up on Siris' post about the problem with blogging, especially the danger of blogging too much about just one subject (i.e., politics, religion, one branch of science). I think his points are well taken. It goes without saying, of course, that losing a sense of perspective can include losing your sense of humor. I realized this when one of my readers, pretty new to the blogging world, sampled the thread below about Brooks' and the End of Philosophy. Here's what he wrote: Yes, there is a real world out there, indepedent of the blogosphere. And that's a happy thought for a Holy Thursday. 2 comments Wednesday, April 08, 2009
Oh, boy. I'm with Brandon on this one. El PZoid hits the nail on the head:
Tip of the hat to Deuce for alerting me to Brooks' piece. 1 comments Bart Ehrman's Book, Interrupted Ben Witherington, in the first of a two-part review of Ehrman's new book: Now it is always a danger to over generalize when we are dealing with as important a matter as the ‘truth about the Bible’. And frankly it is simply untrue to say that most scholars or the majority of Bible scholars or the majority of serious critical scholars would agree with Bart Ehrman in his conclusions about this or that NT matter. NT scholarship is a many splintered thing, and Ehrman’s position certainly does not represent a majority view, or the critical consensus about such matters. At best, one has to say yes and no repeatedly to what Bart takes as the critical consensus about such matters. Bart Ehrman, like the more radical members of the Jesus Seminar (e.g. Robert Funk cf. Robert Price) represents a minority position which has indeed been very vocal in proselytizing for their point of view. So this book should have come with a caveat emptor--- “Buyer Beware: Hyperbolic claims about what most or the majority of critical scholars of the NT think will be frequent in this tome”. The appeal to authority or expertise in any case does not really settle much. The issue is—what is the evidence and why should we draw this or that conclusion? The other issue is--- why mislead the general public about what “the majority of serious critical scholars” have been saying? Perhaps an end run has been done from the outset--- you define a small circle of scholars as the serious ones, the critical ones, the real scholarly thinkers, the real historians, and then having defined your own group narrowly enough, you then say—“the majority of such people think…” Evangelicals are sometimes just as guilty of this ploy as others, but in any case, it does not help when one misrepresents the actual state of play of things among scholars to the general public.Anachronistic reading is Ehrman's specialty, and it sure seems to sell. 0 comments Saturday, April 04, 2009
Siris has a very thoughtful--and I think quite accurate--post about the risks of apologetics and blogging. 0 comments Thursday, April 02, 2009
Critical Thinking in the Classroom * I recently got acquainted with a young instructor who teaches science to seventh-graders at an evangelical school. He's a graduate of Wheaton College and a recent convert to Catholicism. This affords him an interesting perspective on how evangelicals handle science in the classroom, in particular how the whole 'teach the controversy' approach trumpeted by Bible science types plays out in practice. The text the school in question ordered for this young teacher's class is Exploring Creation with General Science. The author, Jay L. Wile, is a young earth Biblical literalist with a Ph.D. in nuclear chemistry. In terms of suggested experiments for kids, my teacher friend tells me that generally the book has a lot to recommend it: great ideas for simple experiments and so forth, and apparently it's a favorite with homeschoolers. So far, so good. But...inevitably the age of the earth has to be discussed. That is, catastrophism: the view of literalists that the earth is only a few thousand years old and much of what geologists have uncovered suggesting otherwise can be explained as the result of a series of cataclysmic events that happened over a very short time, to fit with a literal interpretation of the Book of Genesis. Modern geologists take a uniformitarian view of the earth, and see the layer upon layer of different strata in the Earth's mantle as evidence of the planet's changes being gradual over billions of years. According to my teacher friend, "Wile pushes catastrophism while 'teaching the controversy.'" He writes, "I talked to the principal about my annoyance with the whole thing and he, being the cool guy that he is, is fine with my particular take on it (Old Earth/Evolution), but still thinks the controversy ought to be taught. "So I've been doing research on uniformitarianism [and] catastrophism and realizing that the idea of putting these two theories in front of seventh graders and, A. expecting them to understand what is going on, much less B. make a real judgment between them, is just beyond absurd. "Until seventh graders have a grounding of basic knowledge about standard geology, there's no point in asking them to determine anything based on classroom presentations of 'evidence' culled from one simplistic textbook and a teacher who knows little about geology." [I'm trying to imagine a similar seventh grade class where the textbook gives an overview of A. The Copenhagen Interpretation of Quantum Mechanics and B. Bohm's Non-local Hidden Variable Model --and expect seventh graders to be able to 'weigh the evidence' and make a judgment about it. Only Earth Science and evolution seem to bother literalists. But I digress.] My correspondent adds, "As soon as I start looking at the various arguments, I realize that creation science, flood geology, Intelligent Design - all of that - makes no real attempt to engage with mainstream science. But, if they're doing science at all, they need to be able to beat the scientists at their own game or there's no point. So in other words, they're not really arguing with scientists. They're arguing with other Christians and using 'science' to bolster their argument: that the Bible requires a particular theology and hermeneutic. Which just means that Christians on the other side, if we want this debate to not be completely won by the loudmouths, have to come up with a compelling hermeneutic and theology." Not surprisingly, the problem makes his approach to class challenging. "We're making a timeline of the ages of the earth in class. I've been looking for a comparable catastrophist timeline explaining the same evidence (as uniformitarianism) and ... not finding it." There are no shortage of Biblical videos to view for the kids as well. "The worst," he writes, "is watching ... and realizing that the guy could be arguing that 'Hitler was bad' and the non-sequiturs and equivocations would make you begin to question his case. "The biggest issue here is how Wile sets up his science book - and, by the way, his attitude strikes me as completely ingenuous the entire time - so as to make it seem like he is presenting a fair case to be judged on the evidence." For example, Wile does a unit in which he attempts to establish, scientifically, the material historical integrity of part of the Bible. "[He] assumes that that same integrity applies to all the different books and literature in the Bible," writes the instructor, "and thus treats Genesis 1-11 as a legitimate historical source with evidence to be weighed in the balance together with radiometric dating, stratigraphy, index fossils, contintental drift, etc. Then he presents uniformitarianism and catastrophism, followed by a list of potential 'problems' with either side. "At the end of which he concludes, 'both uniformitarianism and catastrophism have difficulties. Regardless of which view you take, you will run into what seem to be unsolvable problems' (Wile 209, emphasis author's)." "If I didn't tend to trust these people since I grew up among them and know their basic sincerity, I would swear they were being actively disingenuous." Not surprisingly, evolution is considered a weakness of the uniformitarian view: "So, which is it? Is there independent evidence for the process of evolution or not? Well, the short answer to this question is 'no.' You will learn more about evolution when you take biology. For right now, however, let's look at what should be the main line of data that relates to evolution." (Wile p. 210, emphasis author's).I did a little googling on the texbook author, Jay Wile, and it seems, like so many proponents of Biblical literalism, he peddles bad faith arguments against evolution. This, for example, comes from a sample lecture promo. In this seminar, Dr. Jay L. Wile, a nuclear chemist, explores the complicated Creation Versus Evolution debate. He discusses Christian attempts to make the Genesis account compatible with the theory of evolution and shows how these attempts fail. The conclusion is that a literal interpretation of Genesis is completely incompatible with the theory of evolution. He then proceeds to show that this is not at all a problem for someone who is both a Christian and a scientist. He presents strong scientific evidence that supports a literal interpretation of Genesis and equally strong scientific evidence that discounts the theory of evolution. He discusses evolutionists' attempts to explain away this data and how such attempts fail. Perhaps the most intriguing part of this seminar comes when Dr. Wile details some of the fantastic life forms on this planet whose existence can never be explained using the theory of evolution. Regardless of how science-oriented you are, this seminar will strengthen your faith and give you an even deeper appreciation for the marvelous Creation that God has given us. Those evil evolutionists... again. What's funny is this lecture is immediately preceded by one dedicated to 'Critical thinking'. One of the biggest failures of our public and private school systems is that they do not teach students how to think critically. In this seminar, Dr. Wile gives you specific suggestions as to how you can teach your child to think critically, regardless of the subject matter that the student is learning. You will learn how to help your student evaluate statements, look for hidden assumptions, find political/social agendas, and discover faulty logic. Although Dr. Wile's area of interest is science, he will show you how critical thinking applies to all academic areas, as well as all facets of your life.This narrow, defensive approach to science may seem fine at the grade school level and even high school level for home schoolers. But what happens when the kids who show a real aptitude for science and interest in pursuing a career... get to college-- and they have to confront not just professors with working labs but fellow students-- and the weak foundations of their Bible 'science' simply don't stand up to scrutiny? How many of these kids will then turn on their faith and consider it all a pack of lies (as Einstein did and others) because their particular branch of Christianity has a deeply faulty attitude to the natural order? * updated to reflect a couple of corrections. Labels: evolution, science education 6 comments Wednesday, April 01, 2009
1 comments Copyright 2009 by Farrellmedia, Inc. All Rights Reserved. |
The victory party is still very, very, very premature; but if the neo-Darwinists don't keep holding it, someone might get the idea that they've been doing nothing but blowing smoke for a century or two for reasons that don't have much to do with a dispassionate search for the truth. And we can't have that.