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Author
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Topic: Response to Howard Van Till
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Paul A. Nelson
Member
Member # 26
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posted 19. October 2002 11:18
Charlie,
Mother (phenotype) + maternal genome /=/ maternal genome. An ovary that builds eggs is not (simply) DNA.
It's question-begging to say, "Well, it's all just the genes in the end anyway." As Ruth Hubbard explains, in relation to the fantasy of Jurassic Park,
quote:
DNA cannot make eggs or anything else on its own, not even more DNA. And scientists cannot get DNA to make eggs, not to speak of whole organisms. Prehistoric mosquitoes in amber are all very nice, but it would take dinosaur eggs, or eggs an awful lot like them, to be able to turn dinosaur DNA into dinosaurs.
R. Hubbard, "Jurassic Park and the myth of DNA," Boston Globe, 19 July 1993, p. 10
However one tells the story, it will not devolve simply to nucleic acid.
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charlie d.
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Member # 159
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posted 19. October 2002 16:00
As I said, the DNA/protein argument as stated in this thread is specious. It is however very fundamentally wrong to say that embryonic development is not determined by the embryo's genome.
Ultimately, despite the very important, fundamental roles of oocyte cytoplasmic factors and of environment in embryonic development, what an embryo will look like depends in large part on its DNA - unless Wells is arguing that the difference between identical and fraternal twins lies in the distribution of proteins in the fertilized zygote, or in their developmental environment, rather than in their genomes. Moreover, if one alters the DNA of an embryo (for instance, by injecting a transgenic piece of DNA), one will alter that embryo's progeny as well, for all future generations (barring reversal mutations), if there are any. No alteration in oocyte cytoplasm or developmental environment, that I know of, can do that.
Finally, it is true that an ovary that builds eggs is not made only of DNA, but it is also true that a mutation in a single gene (SRY) on the Y chromosome can turn a male into an ovary-bearing, egg-producing female (and the same gene, unmutated, turns trasngenic female mice into males).
[ 19. October 2002, 16:02: Message edited by: charlie d. ]
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Frances
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Member # 169
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posted 19. October 2002 16:09
Paul,
I suggest that one carefully re-read the statements made by the original posters. They are NOT claiming that religious people cannot do science but that foundations [moderator edit] can be helpful in understanding the source of one's potential biases.
I am not qualified to discuss Wells' PhD work and paper. I understand that most of the work was published by other authors
quote:
[A] “Confocal Microscopy Analysis of Living Xenopus Eggs and the Mechanism of Cortical Rotation,” Development 122 (April, 1996): 1281-1289; “Microtubule-mediated organelle transport and localization of beta-catenin to the future dorsal side of Xenopus eggs,” Proceedings of the National Academy of Sciences USA 94 (February, 1997): 1224-1229.
Source
While Wells' article does not mention the authors but a quick search on PNAS finds the following
Brian A. Rowning, Jonathan Wells, Mike Wu, John C. Gerhart, Randall T. Moon, and Carolyn A. Larabell
Microtubule-mediated transport of organelles and localization of -catenin to the future dorsal side of Xenopus eggs
and
Larabell, C.A., Rowning, B.A., Wells, J., Wu, M. and Gerhart, J.C. 1996. Confocal microscopy analysis of living Xenopus eggs and the mechanism of cortical rotation. Development 122
thus whether or not the ideas in these papers are amateurish are beyond my capacity. But I believe the original author was not refering to the papers directly.
While motives may be helpful, I find it more relevant to discuss the actual claims made in research. So lets try to focus on whether or not such claims are supportable. That's how science works anyway. Leave the rethoric for the "popular press" :-)
As far as the Xenopus is concerned, the embryological development and the various signaling is fascinating a topic to me
An example of for instance the wingless pathway in drosophila and in the xenopus seem to be descibed in terms of genes encoding the proteins
quote:
The wingless pathway has been resolved by genetic dissection and is described in terms of the genes encoding the proteins in the pathway:
wingless -> frizzled ->dishevelled -| zw3/shaggy -| armadillo -> cell fate
Source
It is fascinating to find that such homologous pathways are to be found in so many an organism.
Laramees paper on beta-catenin raised some interesting questions which seem to have been resolved partially by Yost et al
quote:
The results show that a serine/threonine kinase, glycogen synthase kinase-3 (Xgsk-3), directly phosphorylates ß-catenin in vitro at an amino terminal site. Deletion or mutation of this site greatly reduces phosphorylation of ß-catenin in embryos, and inhibition of endogenous Xgsk-3 with a dominant negative protein also reduces phosphorylation of ß-catenin
Source
The following web site by Moon A Pond in Seattle seems to have some useful links
For Wingless the following relevant papers seem to show how genes initiate proteins used for signaling
quote:
Wnt genes encode a family of secreted glycoproteins that modulate cell fate and behavior in embryos through activation of receptor-mediated signaling pathways. Wnt sequences, patterns of expression and activities are highly conserved in evolution, so it has been possible to gain insights into the functions, and mechanisms of action, of the Wnt genes through a synthesis of genetic and cell biological approaches in different organisms. These studies suggest that there are functionally distinct WNT proteins as assayed by the ability to transform cells and by differences in embryonic responses to ectopic WNT signals. Moreover, gain-of-function and loss-of-function studies both support the involvement of Wnt proteins in modulating cell fate and cell behavior during vertebrate development, often through combinatorial interactions with other signaling pathways to regulate gene expression.
From Trends Genet 1997 Apr;13(4):157-62 Moon RT, Brown JD, Torres M.
and this paper
Mechanism and function of signal transduction by the Wnt/beta-catenin and Wnt/Ca2+ pathways.
Miller JR, Hocking AM, Brown JD, Moon RT.
quote:
Communication between cells is often mediated by secreted signaling molecules that bind cell surface receptors and modulate the activity of specific intracellular effectors. The Wnt family of secreted glycoproteins is one group of signaling molecules that has been shown to control a variety of developmental processes including cell fate specification, cell proliferation, cell polarity and cell migration. In addition, mis-regulation of Wnt signaling can cause developmental defects and is implicated in the genesis of several human cancers. The importance of Wnt signaling in development and in clinical pathologies is underscored by the large number of primary research papers examining various aspects of Wnt signaling that have been published in the past several years. In this review, we will present a synopsis of current research with particular attention paid to molecular mechanism of Wnt signal transduction and how the mis-regulation of Wnt signaling leads to cancer.
[ 19. October 2002, 16:43: Message edited by: Moderator ]
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rafe gutman
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Member # 134
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posted 19. October 2002 19:37
i agree with the moderator that discussing motivations is totally inappropriate for this forum, and that it would be unfair to single out wells from all the other ID advocates. however, david's posts did contain some interesting parts about wells' conclusions, and i'd ask that he be allowed to repost those parts, since many other posts have been made since then continuing that portion of the discussion. i'm going to requote wells below, since it is essential to this discussion:
quote:
from here
"According to the standard view, the development of an embryo is programmed by its genes-its DNA. Change the genes, and you can change the embryo, even to the point of making a new species. In the movie "Jurassic Park," genetic engineers extract fragments of dinosaur DNA from fossilized mosquitoes, splice them together with DNA from living frogs, then inject the combination into ostrich eggs which had had their own DNA inactivated. In the movie, the injected DNA then re- programmed the ostrich to produce a dinosaur. Experiments similar to this have actually been performed, though not with dinosaur DNA.
In every case, if any development occurred at all it followed the pattern of the egg, not the injected foreign DNA. While I was at Berkeley I performed experiments on frog embryos. My experiments focused on a reorganization of the egg cytoplasm after fertilization which causes the embryo to elongate into a tadpole; if I blocked the reorganization, the result was a ball of belly cells; if I induced a second reorganization after the first, I could produce a two-headed tadpole. Yet this reorganization had nothing to do with the egg's DNA, and proceeded quite well even in its absence (though the embryo eventually needed its DNA to supply it with additional proteins).
So DNA does not program the development of the embryo. As an analogy, consider a house: the builder needs materials (such as pieces of lumber cut to the right lengths, cement, nails, piping, wiring, etc.), but he also needs a floor plan (since any given pile of materials could be assembled into several different houses) and he needs a set of assembly instructions (since assembling the roof before the foundation and walls would pose a serious problem). In a developing organism, the DNA contains templates for producing proteins-the building materials.
To a very limited extent, it also contains information about the order in which those proteins should be produced-assembly instructions. But it does not contain the basic floor plan. The floor plan and many of the assembly instructions reside elsewhere (nobody yet knows where). Since development of the embryo is not programmed by the DNA, the Darwinian view of evolution as the differential survival of DNA mutations misses the point."
(emphasis mine)
i'm not sure why paul continues to insist that ID critics don't realize that DNA isn't the "all in all" of development. yes, naked DNA is inert, we all understand this. the DNA of almost every cell in our body is identical, so obviously something else is going on to make them behave differently. at issue are statements like:
"DNA does not program the development of the embryo"
considering that he's arguing that proteins are programming the development of the embryo, and that the DNA encodes these proteins, you could at most argue that DNA and proteins together program the development of the embryo. i think a better way to say it is that gene expression programs the development of the embryo. i suppose we could go back and forth on this one, and it'd mostly be a semantic argument, until you see what he concludes based on his previous statement:
"Since development of the embryo is not programmed by the DNA, the Darwinian view of evolution as the differential survival of DNA mutations misses the point".
now this is where wells gets himself into trouble. wells likes to do this a lot. he'll make a statement that's sorta true, depending on how you interpret it, then follow it up with a statement that is only true if you use the wrong interpretation of the first statement. as charlie mentioned earlier, since a xenopus oocyte is so large it has enough protein content to undergo several rounds of division (the total volume remains the same) without the need for protein replenishment through transcription/translation. in that sense, you might be able to interpret wells' initial statement as true, DNA does not program the development of the embryo. the key player is the proteins produced by the maternal genome prior to fertilization. since experiments concerning genome replacement (cloning) were mentioned, this distinction becomes important. "In every case, if any development occurred at all it followed the pattern of the egg, not the injected foreign DNA". i'm not sure if a agree with this statement, i guess it would depend on how "foreign" the foreign DNA is, but let's assume this is true for now. then again, this would support one interpretation of his initial statement.
however, naturally-occuring mutations that occur in the maternal genome could have an impact on the development of her eggs. if the mutation causes a subtle increase in expression of a growth factor, then the mutant offspring might be a little larger and possibly have a selectable advantage. you can't argue that darwinism would play no role here. so "the Darwinian view of evolution as the differential survival of DNA mutations misses the point" would only be a defendible conclusion if interpreted his first statement incorrectly. that is, if DNA played no role in development.
i think this was the "amateurish" mistake by wells that david alluded to in his now-deleted post.
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Paul A. Nelson
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Member # 26
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posted 20. October 2002 11:40
Jonathan Wells has a new book in preparation, with the working title "The End of the Genetic Paradigm," where he lays out his case for a better understanding of heredity. While awaiting that book -- which promises to be every bit as readable (and controversial) as Icons of Evolution -- I'll suggest What Genes Can't Do (MIT Press, 2002), by Lenny Moss. I think some of us on the ID side of the aisle (where DNA is a very popular and much-worshipped molecule indeed!) are struggling to express a more adequate conception of biological function and form -- namely, one in which the organism does not disappear in favor of any one of its parts.
Moss, who I stress is not a design theorist, puts it this way:
quote:
The structural organization of the cell, the basic membrane system and the compartmentalization which it embodies, is passed on from one generation to the next by way of the maternal egg cell, and if lost neither "all the kings horses and all the kings men," nor any amount of DNA, can put it back together again.
Now obviously no one reading this thread is going to deny this. Only a cell is a cell. But I can almost hear "Yet DNA is still at the foundation of things...nevertheless, genes are running the show..." (and so on). So the debate over the best ontology of life will go on. ![[Smile]](smile.gif)
I must bow out of this and other threads for a week, for a lecturing and research trip to Southern California. Another plug: Anyone in the LA area who wants to say hello should stop by Chase Gymnasium at Biola University, on Thursday, October 24, at 7:00 pm. The program is "Darwinism in Crisis," with Jed Macosko, Bill Dembski, Jonathan Wells, John Bloom, Fuz Rana, Hugh Ross, and me.
[ 20. October 2002, 12:06: Message edited by: Paul A. Nelson ]
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Frances
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Member # 169
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posted 20. October 2002 12:50
Paul,
Good to hear that Wells has a new book in store. I do hope though that Wells will try to avoid the controversy surrounding Icons which is imho largely caused by an incompleteness of his treatment of the icons (Peppered Moth comes to mind for instance). I would not promote the book as being readable in this sense since much of what is known about these topics seems to be left unaddressed in Icons.
I wish that I lived close enough to attend the conference "Darwinism in crisis". I have heard much about this crisis in the past from a primarily religious angle and would love to hear more about whether or not there is scientific support for this 'crisis' ? And although I understand that ID relies on such crises, I wonder if it would not be better for ID to come up with their own scientific hypotheses.
Perhaps it's time to address Intelligent design's struggle with its identity?
quote:
In conclusion, it is crucial to note that design theory is at best a supplementary consideration introduced along- side (or perhaps into, by way of modification) neo-Darwinian biology and self- organizational complexity theory. It does not mandate the replacement of these highly fruitful research paradigms, and to suggest that it does is just so much overblown, unwarranted, and ideologically driven rhetoric. Intellectual honesty demands that the wide-range of flexibility as regards the interpretation and significance of design theory be made abundantly clear. The dutiful avoidance of dogmatism, an irenic attitude, and a healthy dose of humility will by themselves, I think, do much to dispel the controversy at Baylor and help open the doors for the acceptance of design theorists as dialogue partners in the wider academic community.
Is this Biola conference similar to the 1999 one organized by the Christian Apologetics department which also touted Darwinism in crisis?
I am glad though that the focus of the crisis is moving from 'evolution in crisis" to "Darwinism in crisis", suggesting that it is the mechanisms of evolution rather than the obvious facts of evolution are in doubt. Even such renowned authors as Denton ("Evolution in crisis") have come to accept the evolutionary view (Nature's destiny).
[ 20. October 2002, 13:13: Message edited by: Frances ]
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rafe gutman
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Member # 134
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posted 21. October 2002 22:34
quote:
paul:
Jonathan Wells has a new book in preparation, with the working title "The End of the Genetic Paradigm," where he lays out his case for a better understanding of heredity....which promises to be every bit as readable (and controversial) as Icons of Evolution
please forgive me for being wary of anyone that answers a question by deferring to "future work". i've seen similar claims made before, only to be disappointed when the work is finally released. of course, i'll have to reserve judgement until i see the product, but hopefully you'll understand why i am skeptical. in the meantime i'll try and check out that book you mention.
quote:
Now obviously no one reading this thread is going to deny this. Only a cell is a cell. But I can almost hear "Yet DNA is still at the foundation of things...nevertheless, genes are running the show..." (and so on). So the debate over the best ontology of life will go on.
you're entitled to your own interpretation of wells' statement. however, as i mentioned in my previous post, the only interpretation of his statement that allows him to conclude that DNA-centric evolution is misplaced is an erroneous one.
considering that wells has not published any research relating to the topic of his book, and the fact that it will be for the lay person, i presume wells will be heavily referencing the work of others. is it possible to get a few references from him when you see him in biola? i'd be really interesting in seeing empirical research that supports the notion that "DNA does not program the development of the embryo".
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charlie d.
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posted 21. October 2002 23:34
Better yet, I am sure there are several experienced geneticists and molecular/developmental biologists who'd be willing to fact-check the book, so that it doesn't run into the same problems of inconsistent scholarship as IoE. If a general outline of topics is provided (of course, we don't want the scoop!), I can probably propose a few names of appropriate reviewers with specific expertise and appropriate (non ultra-reductionist) mindset.
I think there is enough to legitimately criticize about excessive genocentrism in biology (and, especially, its popularization), without having to sacrifice scientific accuracy. (Indeed, several good scientists have already written books on the topic, such as Lewontin and Fox Keller.)
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djmullen
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posted 22. October 2002 06:40
Despite warning about how our discussion board operates, this user continued to post on religious motivations. His post has been deleted.
[ 22. October 2002, 21:37: Message edited by: Moderator ]
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Xenon
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posted 22. October 2002 09:46
In his post, Xenon tells me, The Moderator,:
The Moderator, it seems to me, needs to make his position clear to the participants of this forum on whether religious motivations qualifies as philosophical motivations, and is thus an adequate discussion topic.
I have been quite clear on this point. Brainstorms has no interest in gaining the interest of other forums. This is not a popularity contest that we are involved in...we are interested in seeing positive ideas developed. When people and their motivations get discussed, I get angry.
[ 22. October 2002, 21:41: Message edited by: Moderator ]
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charlie d.
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Member # 159
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posted 22. October 2002 10:14
This is probably irrelevant in this thread, but since it has been brought up, I might just put in my $0.02.
I have to say I largely disagree with David on this one. In my experience, I found that most people who enter science, even from deeply religious backgrounds, do so with an open mind and an understanding of what the pursuit of scientific knowledge may lead to. Most of these people do not later abandon religion, though often renounce those aspects of its teachings (e.g. biblical literalism) that obviously contrast with empirical experience (the most common justification being that God would not lie to us through our minds and senses). I personally know several deeply religious scientists, many of whom make no mistery of their religiousness. Several prominent biologists are religious, Francis Collins being probably the best known. (I should also say that much of the selection is of course done at the beginning: it is rather rare for religious fundamentalists to enter science in the first place.)
My point here is not that religious beliefs don't influence scientific attitudes, interpretations and approaches. However, I do not think religion is any harder to "overcome" than any other form of strongly held intellectual background (philosophical, political etc), as long as science is embraced in good faith. Indeed, it may not need to be overcome at all.
Basically, I think the positive or negative impact of one's belief system on scientific production should definitely be evaluated on a strict case-by-case basis. Also, just like Lewontin's Marxism has certainly influenced him and his scientific production, it has also enriched the scientific discourse, as much as one can disagree with some of his arguments. Science, like all human activities, can only prosper from a diversity of high quality intellectual inputs.
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Xenon
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Member # 435
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posted 23. October 2002 10:22
Xenon,
If you want to talk, send me an email:
moderator@iscid.org
Two points:
1. In one of your posts you did in fact indicate that I should allow this discussion to continue, if for no other reason than the fact that it would become a popular topic. This is exactly what I DO NOT WANT. I don't want for there to be a popular topic for the wrong reasons.
2. You are accusing me of being biased. From my vantage point, this is simply evidence that you are not here to participate in the Brainstorms' method of discussion. Rather, it has become quite evident that you are here only to stir the pot and engage in WCW style combat. I try my best to apply my criteria even handedly. Unfortunately, while some people take my moderating with grace, it turns out that some become bitter and take it as a personal insult. Complaining and whining simply confirm to me that I was correct in my actions and that you are not the type of person I want participating at Brainstorms.
Your next response to me needs to be via email.
[ 23. October 2002, 11:22: Message edited by: Moderator ]
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Mark Szlazak
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Member # 391
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posted 23. October 2002 10:58
Paul, here's a couple more books that sound like Moss.
It Ain't Necessarily So: The Dream of the Human Genome and Other Illusions
by Richard C. Lewontin
The Century of the Gene
by Evelyn Fox Keller, L. L. Winship
[ 23. October 2002, 10:59: Message edited by: Mark Szlazak ]
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