Of Behe and Snake Venom
by GutsI've been commenting lately on tidbits I find interesting in various critiques of Michael Behe's new book Edge of Evolution . The latest one posted at the pandas thumb ironically supports several of Mike Gene's recent posts .
The reviewer states:
Is Someone actively designing rattlesnake (Sistrurus catenatus) venom in the American Midwest [7] and fine-tuning the specificity of black mamba (Dendroaspis polylepis) toxins for subtypes of mammalian muscarinic acetylcholine receptors [8]?
The answer is obviously that one wouldn't have to, because snake venom itself apparently only had to appear once, as far back as a few hundred million years ago.
…the tissue types from which the toxin recruitment genes were selected were as diverse as the proteins themselves. Two toxin types (CRISP and kallikrein) actually appear to be modifications of proteins already present in the ancestral salivary tissue. While the activity of the ancestral protein has been invariably retained, toxin types originating from extensively cysteine cross-linked proteins have been the ones to flourish into newly derived, functionally diverse, toxin multigene families.
here
More accessible reviews can be found here and here
November 1st, 2007 at 12:47 am
And the name of the reviewer is none other than Nicholas J. Matzke. How about that. It seems the front loading message is sinking in even if it is currently at a subliminal level. Nick may yet be converted. Pandas lie down next to bunnies. Indeed there is hope in the world.
Comment by Bradford — November 1, 2007 @ 12:47 am
November 1st, 2007 at 2:29 am
So you're saying snake venom functionality was frontloaded into the original design of all these proteins with different original functions?
Comment by Nick Matzke — November 1, 2007 @ 2:29 am
November 1st, 2007 at 2:46 am
don't know if it was itself frontloaded but it did not evolve from scratch.
Comment by Guts — November 1, 2007 @ 2:46 am
November 1st, 2007 at 3:04 am
Since on standard evolutionary theory ever since Darwin, virtually nothing ever evolves "from scratch", I'm not sure why we should find this surprising…
Comment by Nick Matzke — November 1, 2007 @ 3:04 am
November 1st, 2007 at 3:17 am
but if you read the links , this is obviously not " standard".
Comment by Guts — November 1, 2007 @ 3:17 am
November 1st, 2007 at 4:09 am
Guts — please state your position in more depth, I have only a vague idea of what you are trying to say. Will be back tomorrow.
Comment by Nick Matzke — November 1, 2007 @ 4:09 am
November 1st, 2007 at 4:21 am
Huh? Do you have any questions? feel free to ask.
Comment by Guts — November 1, 2007 @ 4:21 am
November 1st, 2007 at 7:41 am
Nick's concluding paragraph is noteworthy:
He imputes motives to Behe for which Behe is criticized.
The significance of randomness in any explanation lies in its capacity to adquately explain an outcome. I would agree with Nick that a random mutation, that is selected because of enhanced reproductive fitness, is not a random outcome. That alone does not answer the question of whether or not a random generator makes sufficient options available for a selection sifter. Of course it also does not answer this question: What random or non-random causes led to the initial genome from which random mutations subsequently occurred?
Having chastized Behe for misusing Behe's own metaphysical predilections Nick now unnecessarily introduces his own into the mix. "We might finally see the edge of creationism, if not the end of it?" Why would that be Nick when the first of the two previously mentioned questions leads to answers with insufficient supporting data in some instances and inadaquate data in all proposed origins scenarios. To use an adjusted phrase of Mark Twain, the death of creationism is presumptuous if science is our guide.
Comment by Bradford — November 1, 2007 @ 7:41 am
November 1st, 2007 at 11:56 am
Well, here is what is confusing me Guts:
* How many times do you think venom proteins (not just "venom") originated?
* Do you think nothing much changed in venom proteins after their origin?
* How is venom evolution far from 'standard'?
Comment by Nick Matzke — November 1, 2007 @ 11:56 am
November 1st, 2007 at 12:25 pm
Nick:
It is all suppositions. But the "fine-tuning" adaptation of most toxin types is probably more recent, in fact. As long as these toxins duplicated in each species and get a particular target, they become specialized in it (a process that is happening even now).
Nick:
The general biochemical scaffold of the original may have been recruited for the snake venom sometime earlier than it was believed.
nick:
Read the links.
Comment by Guts — November 1, 2007 @ 12:25 pm
November 1st, 2007 at 1:01 pm
Bradford wrote:
Quite so. Randomness in state lotteries, roulette, bingo, or in picking a child to answer a question in a classroom full of raised arms and eager faces does not entail that random unintentional processes generated state lotteries, roulette, bingo, or elementary schoolteaching. Nor that such processes are sufficient to explain why there are such things as state lotteries, roulette, bingo, or elementary schoolteaching. If Behe thinks that the randomness we see in biology (he surely doesn't deny that there is some) is like these cases and not like whether a particular drop of rain falls on a particular blade of grass, then Matzke's criticism is off-base.
Comment by stunney — November 1, 2007 @ 1:01 pm
November 1st, 2007 at 2:18 pm
stunney, so to put it tersely, randomness within boundries, or chaos under control. This is how the known systems in nature, from quantum level to macro level bioforms, and human engineering work. Even in religion this can be seen where there is freedom within boundries. Which reminds me of when I was a much younger man puzzling over questions of man free will vs God's "sovereignty", etc. One day I found myself at Disneyland driving around one of those little cars on the tracks, and I had my answer. You have a measure of freedom within the boundries of the track. All kinds of chaos and erratic driving can take place within the boundries, but none of that is responsible for the preexisting boundries themselves. True with God (in my opinion), and true with nature.
Random mutations have been seen to cause effects in genomes. But as the darwinists admit themselves, the boundries that limit the range are not random. It's an ingenious system. Very intelligent indeed.
Comment by kornbelt888 — November 1, 2007 @ 2:18 pm
November 1st, 2007 at 3:28 pm
Before I wrote this review I talked with Brian Fry, the guy interviewed in the links. Plus I've read his articles and a bunch of others on the topic. It all looks like perfectly standard duplication-mutation-selection to me and to him as far as I can tell. So please give us a bit more than "read the links."
Comment by Nick Matzke — November 1, 2007 @ 3:28 pm
November 1st, 2007 at 4:27 pm
I'm referring to this:
Which is in the second link in my post.
Comment by Guts — November 1, 2007 @ 4:27 pm
November 1st, 2007 at 6:06 pm
Eh? First of all, that has nothing to do with snake venom, and second it's in a comment so how was anyone supposed to know that's what you were talking about, and third that's a fusion of a Sean Carroll quote and a quote from Ernst Mayr that Carroll is quoting (and Carroll is noting Mayr was wrong about that — big whoop, Mayr was writing while genes were primarily "bean bags" and little was known about their biochemistry. Mayr himself emphasized the importance of borrowing and cooption in the evolution of complex structures again and again, so it is hard to see why the extension of this further back to genes should cause any problems.).
Unless you are going to say that snake venom proteins were front-loaded into original protein design or something, you haven't got any argument at all. In that case we go back to the standard interpretation of the science, stated in my review of Behe, which establishes:
1. Dozens of different venom proteins have evolved from non-venomous ancestors, often evolving new protein-protein binding sites in the process (you say this is "speculation" — do me a favor and read Fry's paper, which you conveniently linked to, and tell us why his peer-reviewed empirical results should be discounted and your random insult favored).
2. The evolution is ongoing and rapid, such that proteins *within* species and *within* subspecies *alive right now* are evolving different binding sites, different regulation, etc., in order to facilitate predation on different prey. (You seem to have completely missed this point.)
3. Therefore Behe is wrong in saying that ridiculously large populations are required to evolve binding sites with high specificity for diverse targets, and if he were paying attention he never would have made the claims he did. If other IDers (a) were at all interested in double-checking his claims instead of just innocently endorsing them as the latest silver bullet against "Darwinism" or (b) had the gumption to challenge the Master of ID then one of them would have made these points long before TREE got around to publishing my review.
If this is the best defense of Behe's "Edge of Evolution" argument that the ID guys can come up with then Behe really is sunk…
Comment by Nick Matzke — November 1, 2007 @ 6:06 pm
November 1st, 2007 at 6:26 pm
Wow that was a bunch of hot air, "nothing to do with snake venom", "tell us why his peer-reviewed empirical results should be discounted ", "You seem to have completely missed this point" , complete and utter nonsense. It doesn't have to be about snake venom, and I completely endorsed and repeated the results in that paper in my post and in my comment. Do me a favor and tell me what that ridiculous rant had to do with the substance of my post.
Comment by Guts — November 1, 2007 @ 6:26 pm
November 1st, 2007 at 10:08 pm
What substance? I said in the review that Behe was wrong, in part because snake venom proteins are, as we speak, evolving different high-specificity binding within modern species and subspecies. This is impossible according to Behe, who thinks it takes huge populations and double-mutants or worse to evolve protein-protein binding sites. In response, you made some vague gestures in the direction of frontloading, and then said on the question of multiple-origin-of-venom-proteins point, "It's all supposition." But it's not supposition at all, Brian Fry and others have demonstrated the multiple origin of venom proteins from diverse sources in peer-reviewed publications.
The only other vaguely substantive comment was that the evolution of snake venom was somehow "nonstandard", and by mind reading, I guess, we were supposed to figure out that you meant Ernst Mayr's view from 40+ years ago, which was incorrect only in that evolutionary relationship could be traced back much further than he then thought.
If you don't really have anything to say in defense of Behe's book, that's fine I guess, but then why put a post on TT that seems to be defending Behe from my critical review?
It all seems unnecessarily circuitous to me. My suspicion is that you guys at Telic Thoughts know that I'm right about Behe's book, but don't want to admit it…
Comment by Nick Matzke — November 1, 2007 @ 10:08 pm
November 2nd, 2007 at 1:50 am
Nick:
My understanding is that Behe doesn't think two new intracellular protein-protein binding sites can evolve de novo at the same time and he leaves out destructive/foreign protein binding. Also, I didn't address that in my post because I haven't completed reading the book and his responses. I just saw your review when I read Macht's recent post. Besides, he is actively responding to criticisms at his amazon blog, so if he doesn't get to you and I still disagree with you, I may address it.
Nick:
What I meant was of course is that this is all inferred from sequence data, no one is actively watching all these duplications occur.
Nick:
Once again, you're wrong. The "non-standard" bit should have been easily gleaned from my post, but it was actually introduced explicitely in the comments as a response to you. I didn't expect anyone to mind read anything, it's all clearly stated in all my links.
Nick:
Thats exactly what I was referring to when I said this: "snake venom itself apparently only had to appear once, as far back as a few hundred million years ago." The idea is that snakes evolved from a common ancestor that already had a "sophisticated" venomous repetoir.
Nick:
Thats a rather bizarre question, there's nothing in my post that would lead someone to believe that I wanted to defend Behe, I was saying something positive about Mike's recent posts. This is like asking — why write a story about different types of wines on a website about wine. The data here supports the idea that new functions primarily arise through reuse of old genes which is relevant to front-loading.
Nick:
lol
Comment by Guts — November 2, 2007 @ 1:50 am
November 2nd, 2007 at 11:42 am
Gut's motivation was apparant immediately to me but then again I've been following posts on a steady basis for some time. This was about FL and if Gut's had an individual in mind it was Mike who is the foremost proponent of FL. He would have posted the same thing had the author been anyone other than you Nick IMO. The fact that it was you simply added some lighthearted side issues to the main point as we know you are an active TT commenter and likely to read the post.
Comment by Bradford — November 2, 2007 @ 11:42 am
November 2nd, 2007 at 11:49 am
Guts' point needs to be stressed. Conclusions favorable to ID are likewise drawn from sequence data. There is no need to invoke the supernatural contrary to knee jerk criticisms so common on the internet.
Comment by Bradford — November 2, 2007 @ 11:49 am
November 2nd, 2007 at 7:04 pm
Bradford:
Like what?
Comment by Raevmo — November 2, 2007 @ 7:04 pm