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Rethinking Genetic Determinism With only 30,000 genes, what is it that makes humans human? By Paul H. Silverman For more than 50 years scientists have operated under a set of seemingly incontrovertible assumptions about genes, gene expression, and the consequences thereof. Their mantra: One gene yields one protein; genes beget messenger RNA, which in turn begets protein; and most critically, the gene is deterministic in gene expression and can therefore predict disease propensities. Yet during the last five years, data have revealed inadequacies in this theory. Unsettling results from the Human Genome Project (HGP) in particular have thrown the deficiencies into sharp relief. Some genes encode more than one protein; others don't encode proteins at all. These findings help refine evolutionary theory by explaining an explosion of diversity from relatively little starting material. We therefore need to rethink our long-held beliefs: A reevaluation of the genetic determinism doctrine, coupled with a new systems biology mentality, could help consolidate and clarify genome-scale data, enabling us finally to reap the rewards of the genome sequencing projects. UNEXPECTED RESULTS In the mid- and late 1980s, our testimony before the congressional committees controlling HGP purse strings relied upon our old assumptions.1 In describing the genome's potential medical value, we elevated the status of the gene in human development and by extension, human health. At the same time, the deterministic nature of the gene entered the social consciousness with talk of "designer" babies and DNA police that could detect future criminals. Armed with DNA determinism, scientific entrepreneurs convinced venture capitalists and the lay public to invest in multi-billion-dollar enterprises whose aim was to identify the anticipated 100,000-plus genes in the human genome, patent the nucleotide sequences, and then lease or sell that information to pharmaceutical companies for use in drug discovery. Prominent among these were two Rockville, Md.-based companies, Celera, under the leadership of J. Craig Venter, and Human Genome Sciences, led by William Haseltine. But when the first draft of the human genome sequence was published in the spring of 2001, the unexpectedly low gene count (less than 30,000) elicited a hasty reevaluation of this business model. On a genetic level, humans, it seems, are not all that different from flies and worms. Or maybe they are, if we can assume that genes are not strictly deterministic. As Venter et al. reported in their genome manuscript: "A single gene may give rise to multiple transcripts, and thus multiple distinct proteins with multiple functions by means of alternative splicing and alternative transcription initiation and termination sites."2 The industry shakeup was predictable. Celera, Human Genome Sciences, and most of the other genomic sequencing firms refocused their business plans and downsized. Venter resigned as president of Celera, and Haseltine has indicated his intention to do the same. Read the rest at The Scientist http://www.the- scientist.com/yr2004/may/research3_040524.html Posted by Robert Karl Stonjek. |
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On Sat, 22 May 2004 22:44:34 +0000 (UTC), Robert Karl Stonjek <rstonjek@bigpond.net.au> wrote: > Rethinking Genetic Determinism With only 30,000 genes, > what is it that makes humans human? By Paul H. Silverman > > For more than 50 years scientists have operated under a > set of seemingly incontrovertible assumptions about genes, > gene expression, and the consequences thereof. Their > mantra: One gene yields one protein; genes beget messenger > RNA, which in turn begets protein; and most critically, > the gene is deterministic in gene expression and can > therefore predict disease propensities. This is total nonsense. I've been teaching about genes that don't make mRNA or proteins for 25 years and I learned about them long before that. > Yet during the last five years, data have revealed > inadequacies in this theory. Unsettling results from the > Human Genome Project (HGP) in particular have thrown the > deficiencies into sharp relief. Some genes encode more > than one protein; others don't encode proteins at all. I've also been teaching students about genes that encode more than one protein for 25 years. > These findings help refine evolutionary theory by > explaining an explosion of diversity from relatively > little starting material. Really? > We therefore need to rethink our long-held beliefs: A > reevaluation of the genetic determinism doctrine, coupled > with a new systems biology mentality, could help > consolidate and clarify genome-scale data, enabling us > finally to reap the rewards of the genome sequencing > projects. This soounds a lot like new-age doublespeak. Who is this guy? > UNEXPECTED RESULTS In the mid- and late 1980s, our > testimony before the congressional committees controlling > HGP purse strings relied upon our old assumptions.1 In > describing the genome's potential medical value, we > elevated the status of the gene in human development and > by extension, human health. At the same time, the > deterministic nature of the gene entered the social > consciousness with talk of "designer" babies and DNA > police that could detect future criminals. Whatever ... > Armed with DNA determinism, scientific entrepreneurs > convinced venture capitalists and the lay public to invest > in multi-billion-dollar enterprises whose aim was to > identify the anticipated 100,000-plus genes in the human > genome, patent the nucleotide sequences, and then lease or > sell that information to pharmaceutical companies for use > in drug discovery. Most experts thought there would be fewer than 50,000 genes. They turned out to be right. > Prominent among these were two Rockville, Md.-based > companies, Celera, under the leadership of J. Craig > Venter, and Human Genome Sciences, led by William > Haseltine. > > But when the first draft of the human genome sequence was > published in the spring of 2001, the unexpectedly low gene > count (less than 30,000) elicited a hasty reevaluation of > this business model. On a genetic level, humans, it seems, > are not all that different from flies and worms. No experts were surprised at this result. > Or maybe they are, if we can assume that genes are not > strictly deterministic. As Venter et al. reported in their > genome manuscript: "A single gene may give rise to > multiple transcripts, and thus multiple distinct proteins > with multiple functions by means of alternative splicing > and alternative transcription initiation and termination > sites."2 > > The industry shakeup was predictable. Celera, Human Genome > Sciences, and most of the other genomic sequencing firms > refocused their business plans and downsized. Venter > resigned as president of Celera, and Haseltine has > indicated his intention to do the same. I think Venter and Haseltine were probably kidnapped by aliens or maybe they've been murdered by the Masons. It's certain that there has to be some kind of world-wide conspiracy in order to explain all these strange happenings. > Read the rest at The Scientist http://www.the- > scientist.com/yr2004/may/research3_040524.html The Scientist is not a credible magazine. Larry Moran |
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In article <c8ol4i$2ur2$1@darwin.ediacara.org>, Robert Karl Stonjek <rstonjek@bigpond.net.au> wrote: >Rethinking Genetic Determinism With only 30,000 genes, what >is it that makes humans human? By Paul H. Silverman ... >Armed with DNA determinism, scientific entrepreneurs >convinced venture capitalists and the lay public to invest >in multi-billion-dollar enterprises whose aim was to >identify the anticipated 100,000-plus genes in the human >genome, patent the nucleotide sequences, and then lease or >sell that information to pharmaceutical companies for use >in drug discovery. Prominent among these were two >Rockville, Md.-based companies, Celera, under the >leadership of J. Craig Venter, and Human Genome Sciences, >led by William Haseltine. > >But when the first draft of the human genome sequence was >published in the spring of 2001, the unexpectedly low gene >count (less than 30,000) elicited a hasty reevaluation of >this business model. On a genetic level, humans, it seems, >are not all that different from flies and worms. ... >The industry shakeup was predictable. Celera, Human Genome >Sciences, and most of the other genomic sequencing firms >refocused their business plans and downsized. Venter >resigned as president of Celera, and Haseltine has >indicated his intention to do the same. As Larry Moran has also indicated, this is complete nonsense. Venter's resignation and the shakeout at Celera had nothing to do with the number of genes found. As I understand it (admittedly from a distance) it had a lot to do with the failure of Celera to find a way to make money from its investiment in sequencing of the human genome. This would be an issue whether there turned out to be 10,000 genes in the human genome or 100,000. If the rest of the article makes as much sense as this part, one can safely ignore its grand prouncements. -- Joe Felsenstein joe@removethispart.gs.washington.edu Department of Genome Sciences and Department of Biology, University of Washington, Box 357730, Seattle, WA 98195-7730 USA |
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>RJK:- Armed with DNA determinism, scientific entrepreneurs >convinced venture capitalists and the lay public to invest >in multi-billion-dollar enterprises >whose aim was to identify the anticipated 100,000-plus >genes in the human genome, patent the nucleotide sequences, >and then lease or sell that information to pharmaceutical >companies for use in drug discovery. Prominent >among these were two Rockville, Md.-based companies, >Celera, under the leadership of J. Craig Venter, and Human >Genome Sciences, led by William Haseltine. > >But when the first draft of the human genome sequence was >published in the spring of 2001, the unexpectedly low gene >count (less than 30,000) elicited a hasty reevaluation of >this business model. On a genetic level, humans, it seems, >are not all that different from flies and worms. ... >The industry shakeup was predictable. Celera, Human Genome >Sciences, and most of the other genomic sequencing firms >refocused their business plans and downsized. Venter >resigned as president of Celera, and Haseltine has >indicated his intention to do the same. JF:- As Larry Moran has also indicated, this is complete nonsense. Venter's resignation and the shakeout at Celera had nothing to do with the number of genes found. As I understand it (admittedly from a distance) it had a lot to do with the failure of Celera to find a way to make money from its investiment in sequencing of the human genome. This would be an issue whether there turned out to be 10,000 genes in the human genome or 100,000. If the rest of the article makes as much sense as this part, one can safely ignore its grand prouncements. JE:- Prof. Felsenstein does know of Haldane's dilemma. He must know that the dilemma was the direct result of the human genome being required to be much larger that it was and the dilemma was only "solved" when the genome was found to be small. However nobody has revised basic population genetics assumptions to be able to explain how such a tiny genome could code for all the heritable human phenotypes. Prof. Felsenstein cannot ignore the simple logic that without a heritable system of genetic epistasis 30-40,000 genes cannot code for all the heritable phenotypes unless a 2nd layer of genetic code that is not DNA/RNA based exists above the DNA/RNA level. Regards, John Edser Independent Researcher (posting from Bonn Germany) P Box 266 Church Pt NSW 2105 Australia edser@tpg.com.au |
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> RJS:- Rethinking Genetic Determinism With only 30,000 > genes, what is it that makes humans human? By Paul H. > Silverman For more than 50 years scientists have operated > under a set of seemingly incontrovertible assumptions > about genes, gene expression, and the consequences > thereof. Their mantra: One gene yields one protein; genes > beget messenger RNA, which in turn begets protein; and > most critically, the gene is deterministic in gene > expression and can therefore predict disease propensities. LM:- This is total nonsense. I've been teaching about genes that don't make mRNA or proteins for 25 years and I learned about them long before that. RJS:- One gene can only yield one polypeptide, but these polypeptides can be woven into more than just the one protein. Many proteins commonly constitute one selectable phenotype, e.g. haemoglobin the red pigment found in the blood which carries both oxygen and carbon dioxide. Thus most protein phenotypes are coded for by more than one gene. Since selection is only possible at the _phenotypic_ level, mostly, groups of genes are _dependently_ selected (selected using the same phenotype). Thus, for the overwhelming majority of genomic genes being "selfish" cannot pay unless that gene's selfishness is mutual to at least all the other genes that code for the one phenotype being selected. > RJK:- Yet during the last five years, data have revealed > inadequacies in this theory. Unsettling results from the > Human Genome Project (HGP) in particular have thrown the > deficiencies into sharp relief. Some genes encode more > than one protein; others don't encode proteins at all. LN:- I've also been teaching students about genes that encode more than one protein for 25 years. JE:- Incorrect. One gene codes for one polypeptide. As Dr Moran well knows, a protein is not the same biological entity as a polypeptide. More than one polypeptide normally constitutes a protein and mostly, more than one protein constitutes one selectable phenotype. Gene centric Neo Darwinists prefer to oversimplify this situation in their attempt to delete epistasis which is defined as _non_ additive. This just means all the genes that _must_ be selected _together_ because they code for the one selectable phenotype. Apparently, these should not be confused with separate somatic phenotypes which are regarded as selectively independent, i.e."additive", L.O. polygenes for human height. Thus the genes that code for the proteins that constitute the protein haemoglobin are _dependently_ selected at that phenotype but the proteins that form the walls of the artery are supposed to constitute an _independent_ somatic phenotype. Clearly this is the case re: body phenotypes but is not the case re: gene fitness because haemoglobin and the proteins that form an artery wall are FITNESS DEPENDENT on each other. A good haemoglobin protein in a blocked artery is selected against because that artery may reduce the _total_ number of _fertile_ forms reproduced into _one_ population by the unfortunate Darwinian selectee who has the faulty artery. A clean artery is selected against by sickle cell anemia for a similar reason. In fact ALL then proteins that form one Darwinian selectee (one fertile form) are FITNESS DEPENDENT. This is clearly seen when two phenotypes incorporate the same gene that coded for just the one polypeptide. Here, just that one gene would be independently selected at TWO separate phenotypes as well as being dependently selected at two phenotypes if more than one gene was requited to code for each independent phenotype. Since the human genome only has 30,000 or so genes but has millions of heritable and thus selectable phenotypes, the same genes must be dependently selected at more than just one phenotype, i.e. genetic epistasis must dominate entirely, human genetics. Yet, non epistasis is still regarded as "inherited" but "not heritable" and thus, "non selectable". Like it or not, genomic genes form _dependent_ selective _webs_ and not just independent selective chains. The Neo Darwinistic model of independently selectable genomic genes is not real. Not a single independently selectable genomic gene has ever been documented within nature. The Neo Darwinian model of independently selectable genes gave birth to the model that just random events that change gene freq. of such genes can now be regarded as "evolution", e.g. genetic drift. They cannot. Such changes can only be validly regarded as temporal variation. To do so is to _grossly_ misuse an oversimplified model. A model is not a theory, it is always, a simplification/over simplification of an existing theory. Such a model can never be validly used to contest and win against the theory it was simplified from. To do so is to turn science into a Mad Hatter's Tea Party. > RKS:- These findings help refine evolutionary theory by > explaining an explosion of diversity from relatively > little starting material. LP:- Really? JE:- The argument is that genetic epistasis must provide the basis for genetic fitness. The gene centric Neo Darwinistic view that fitness epistasis is "inherited" but "not heritable" must be discarded. Redefining ftness epistasis as additive simply deletes all fitness epistasis and is yet another Mad Hatter solution because not a single independent in fitness genomic gene has ever been documented within nature. > RKS:- We therefore need to rethink our long-held beliefs: > A reevaluation of the genetic determinism doctrine, > coupled with a new systems biology mentality, could help > consolidate and clarify genome-scale data, enabling us > finally to reap the rewards of the genome sequencing > projects. LQ:- This soounds a lot like new-age doublespeak. Who is this guy? JE:- It is Dr Moran who employs "new-age doublespeak", L.R. who employs post modern epistemology because he regards just a random process as being testably causative to something when it remains impossible to test for such causation. At all times, random patterns can validly be supposed to be caused by _either_ random or non random processes. Thus the observation of just a random pattern such as a random genetic drift is NEVER definitive to just a random process. >snip< > RJK:- Armed with DNA determinism, scientific entrepreneurs > convinced venture capitalists and the lay public to invest > in multi-billion-dollar enterprises whose aim was to > identify the anticipated 100,000-plus genes in the human > genome, patent the nucleotide sequences, and then lease or > sell that information to pharmaceutical companies for use > in drug discovery. LS:- Most experts thought there would be fewer than 50,000 genes. They turned out to be right. JE:- Starting from Haldane's Dilemma and moving on, most _required_ 100,000's of genes because genetic epistasis was not allowed as heritable and thus selectable, information. If we restrict all known heritable human phenotypes to just 1 million then each gene codes for, on average, 33.3 phenotypes. How is it possible to delete genetic epistasis from such a situation? Clearly nature is not just using one polypeptide within one selectable phenotype she is being much more efficient. If such events remain regarded as "inherited" but "not heritable" and thus "selectable", how can the system work with just 30,000 or so genes? > RJK:- Prominent among these were two Rockville, Md.-based > companies, Celera, under the leadership of J. Craig > Venter, and Human Genome Sciences, led by William > Haseltine. But when the first draft of the human genome > sequence was published in the spring of 2001, the > unexpectedly low gene count (less than 30,000) elicited > a hasty reevaluation of this business model. On a genetic > level, humans, it seems, are not all that different from > flies and worms. LT:- No experts were surprised at this result. JE:- Dr Moran's comment is simply not credible. Haldane's dilemma was only finally solved, after the human genome project demonstrated that gene centric calculations based on Fisher and Haldane's assumptions: only additive gene associations are heritable and thus selectable (requiring an enormous genome to be able to code for all the heritable differences between man and chimp), was discovered to be redundant. A tiny genome more efficiently used, i.e. that allowed more than one gene that codes for one polypeptide to be used within more than just one selected phenotype is the only possible solution if DNA/RNA is alone considered to provide genetic code. Of course it has been known for over 40 years that more than just DNA/RNA systems provides a genetic code. Sonniborn demonstrated that the cell cortex can provide heritable information that was not based on DNA/RNA. He rearranged a patch cilia in single celled forms to be cut out and reversed so the cell swam in circles. This was passed on over countless generations. Prions form a "prima face" case for proteins coding for protein folding information. If a 2nd layer of heritable material exists above the DNA/RNA level then the two systems acting _together_ would provide a _levered_ system of inheritance, i.e. a system where tiny changes provide many different codes only requiring a tiny DNA/RNA base. The blinkered view of gene centric Neo Darwinists that bean bag population genetics can provide all the answers is not credible. Such models are useful but have been painfully misused. > RJS:- Or maybe they are, if we can assume that genes are > not strictly deterministic. As Venter et al. reported in > their genome manuscript: "A single gene may give rise to > multiple transcripts, and thus multiple distinct proteins > with multiple functions by means of alternative splicing > and alternative transcription initiation and termination > sites."2 The industry shakeup was predictable. Celera, > Human Genome Sciences, and most of the other genomic > sequencing firms refocused their business plans and > downsized. Venter resigned as president of Celera, and > Haseltine has indicated his intention to do the same. LU:- I think Venter and Haseltine were probably kidnapped by aliens or maybe they've been murdered by the Masons. It's certain that there has to be some kind of world-wide conspiracy in order to explain all these strange happenings. JE:- No, just gene centric Neo Darwinistic intransigence. Dr Moran refuses to take a non biased view and allows non testable theory as science to maitain his position. > RJS:- Read the rest at The Scientist http://www.the- > scientist.com/yr2004/may/research3_040524.html LV:- The Scientist is not a credible magazine. JE:- Yes, only the non testable dictates of Dr Moran et al are allowed as credible. Respectfully, John Edser Independent Researcher PO Box 266 Church Pt NSW 2105 Australia edser@tpg.com.au |
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RJS:- Rethinking Genetic Determinism With only 30,000 genes, what is it that makes humans human? By Paul H. Silverman For more than 50 years scientists have operated under a set of seemingly incontrovertible assumptions about genes, gene expression, and the consequences thereof. Their mantra: One gene yields one protein; genes beget messenger RNA, which in turn begets protein; and most critically, the gene is deterministic in gene expression and can therefore predict disease propensities. LM:- This is total nonsense. I've been teaching about genes that don't make mRNA or proteins for 25 years and I learned about them long before that. RJS:- One gene can only yield one polypeptide, but these polypeptides can be woven into more than just the one protein. Many proteins commonly constitute one selectable phenotype, e.g. haemoglobin the red pigment found in the blood which carries both oxygen and carbon dioxide. Thus most protein phenotypes are coded for by more than one gene. Since selection is only possible at the _phenotypic_ level, mostly, groups of genes are _dependently_ selected (selected using the same phenotype). Thus, for the overwhelming majority of genomic genes being "selfish" cannot pay unless that gene's selfishness is mutual to at least all the other genes that code for the one phenotype being selected. RJK:- Yet during the last five years, data have revealed inadequacies in this theory. Unsettling results from the Human Genome Project (HGP) in particular have thrown the deficiencies into sharp relief. Some genes encode more than one protein; others don't encode proteins at all. LN:- I've also been teaching students about genes that encode more than one protein for 25 years. JE:- Incorrect. One gene codes for one polypeptide. As Dr Moran well knows, a protein is not the same biological entity as a polypeptide. More than one polypeptide normally constitutes a protein and mostly, more than one protein constitutes one selectable phenotype. RAGLAND: The article states, "One gene can only yield one polypeptide, but these polypeptides can be woven into more than just the one protein." Is this true? Is the question one gene can only yield one polypeptide framed incorrectly in light of genetic epistasis? If genes are not the causative factor in selecting phenotype then how can we possibly be able to unravel the secrets of our DNA? Isn't it likely at least with some genetic diseases the "gene- centric" model will prove itself? Perhaps some traits are more epistatic than others. For example, traits such as aggression and intelligence are arguably epistatic based. Certainly, it can be argued science will come up with genetic engineering which will eliminate certain genetic diseases before we can genetically engineer certain aspects of intelligence and aggression. JE: Gene centric Neo Darwinists prefer to oversimplify this situation in their attempt to delete epistasis which is defined as _non_ additive. This just means all the genes that _must_ be selected _together_ because they code for the one selectable phenotype. Apparently, these should not be confused with separate somatic phenotypes which are regarded as selectively independent, i.e."additive", e.g. polygenes for human height. Thus the genes that code for the proteins that constitute the protein haemoglobin are _dependently_ selected at that phenotype but the proteins that form the walls of the artery are supposed to constitute an _independent_ somatic phenotype. Clearly this is the case re: body phenotypes but is not the case re: gene fitness because haemoglobin and the proteins that form an artery wall are FITNESS DEPENDENT on each other. A good haemoglobin protein in a blocked artery is selected against because that artery may reduce the _total_ number of _fertile_ forms reproduced into _one_ population by the unfortunate Darwinian selectee who has the faulty artery. A clean artery is selected against by sickle cell anemia for a similar reason. In fact ALL then proteins that form one Darwinian selectee (one fertile form) are FITNESS DEPENDENT. This is clearly seen when two phenotypes incorporate the same gene that coded for just the one polypeptide. Here, just that one gene would be independently selected at TWO separate phenotypes as well as being dependently selected at two phenotypes if more than one gene was requited to code for each independent phenotype. Since the human genome only has 30,000 or so genes but has millions of heritable and thus selectable phenotypes, the same genes must be dependently selected at more than just one phenotype, i.e. genetic epistasis must dominate entirely, human genetics. Yet, non epistasis is still regarded as "inherited" but "not heritable" and thus, "non selectable". RAGLAND: You write, "Yet non-epistasis is still regarded as "inherited" but not "heritable" and thus "non-selectable". Don't you mean epistasis is still regarded as inherited but not heritable and thus non-selectable? What is the difference between inherited and heritable? Isn't this splitting hairs? JE: Like it or not, genomic genes form _dependent_ selective _webs_ and not just independent selective chains. The Neo Darwinistic model of independently selectable genomic genes is not real. Not a single independently selectable genomic gene has ever been documented within nature. RAGLAND: What about the gene for sickle cell anemia? JE: The Neo Darwinian model of independently selectable genes gave birth to the model that just random events that change gene freq. of such genes can now be regarded as "evolution", e.g. genetic drift. They cannot. Such changes can only be validly regarded as temporal variation. RAGLAND: What is the difference between random genetic drift and temporal variation? JE: To do so is to _grossly_ misuse an oversimplified model. A model is not a theory, it is always, a simplification/over simplification of an existing theory. Such a model can never be validly used to contest and win against the theory it was simplified from. To do so is to turn science into a Mad Hatter's Tea Party. RKS:- These findings help refine evolutionary theory by explaining an explosion of diversity from relatively little starting material. LO:- Really? JE:- The argument is that genetic epistasis must provide the basis for genetic fitness. The gene centric Neo Darwinistic view that fitness epistasis is "inherited" but "not heritable" must be discarded. Redefining ftness epistasis as additive simply deletes all fitness epistasis and is yet another Mad Hatter solution because not a single independent in fitness genomic gene has ever been documented within nature. RAGLAND" I think sickle cell anemia is an exception. It conferred protection against malaria. I tend to agree with what your saying but the reply is "So what"? Science is currently not advanced enough to understand genetic epistasis and to be able to influence it. It's much like my writing about aggression. We know hardly nothing about its biological underpinnings. Perhaps you are writing to attempt to create a shift in attitude away from the neo- Darwinian gene-centric view but I would argue that will only come when enough scientific discoveries have been made it discredit it. RKS:- We therefore need to rethink our long-held beliefs: A reevaluation of the genetic determinism doctrine, coupled with a new systems biology mentality, could help consolidate and clarify genome-scale data, enabling us finally to reap the rewards of the genome sequencing projects. LP:- This soounds a lot like new-age doublespeak. Who is this guy? JE:- It is Dr Moran who employs "new-age doublespeak", i.e. who employs post modern epistemology because he regards just a random process as being testably causative to something when it remains impossible to test for such causation. RAGLAND: What are Dr. Moran's views on genetic epistasis versus neo-Darwinian gene-centrism. Does he take sides or does he accomodate both views. Can both views be reconciled with each other? JE: At all times, random patterns can validly be supposed to be caused by _either_ random or non random processes. Thus the observation of just a random pattern such as a random genetic drift is NEVER definitive to just a random process. RAGLAND: I think Dr. Moran understands natural selection and random drift are not necessarily mutually exclusive processes. snip< RJK:- Armed with DNA determinism, scientific entrepreneurs convinced venture capitalists and the lay public to invest in multi-billion-dollar enterprises whose aim was to identify the anticipated 100,000-plus genes in the human genome, patent the nucleotide sequences, and then lease or sell that information to pharmaceutical companies for use in drug discovery. LQ:- Most experts thought there would be fewer than 50,000 genes. They turned out to be right. JE:- Starting from Haldane's Dilemma and moving on, most _required_ 100,000's of genes because genetic epistasis was not allowed as heritable and thus selectable, information. If we restrict all known heritable human phenotypes to just 1 million then each gene codes for, on average, 33.3 phenotypes. How is it possible to delete genetic epistasis from such a situation? Clearly nature is not just using one polypeptide within one selectable phenotype she is being much more efficient. If such events remain regarded as "inherited" but "not heritable" and thus "selectable", how can the system work with just 30,000 or so genes? RAGLAND: LR. Edser have you asked Moran what his views on genetic epistasis are? I get the impression Dr. Moran doesn't beleve in genetic epistasis from reading your response. I have not read what Dr, Moran's views are on this so it would be helpful for him to respond to your tar and feathering. RJK:- Prominent among these were two Rockville, Md.-based companies, Celera, under the leadership of J. Craig Venter, and Human Genome Sciences, led by William Haseltine. But when the first draft of the human genome sequence was published in the spring of 2001, the unexpectedly low gene count (less than 30,000) elicited a hasty reevaluation of this business model. On a genetic level, humans, it seems, are not all that different from flies and worms. LS:- No experts were surprised at this result. JE:- Dr Moran's comment is simply not credible. Haldane's dilemma was only finally solved, after the human genome project demonstrated that gene centric calculations based on Fisher and Haldane's assumptions: only additive gene associations are heritable and thus selectable (requiring an enormous genome to be able to code for all the heritable differences between man and chimp), was discovered to be redundant. A tiny genome more efficiently used, i.e. that allowed more than one gene that codes for one polypeptide to be used within more than just one selected phenotype is the only possible solution if DNA/RNA is alone considered to provide genetic code. Of course it has been known for over 40 years that more than just DNA/RNA systems provides a genetic code. Sonniborn demonstrated that the cell cortex can provide heritable information that was not based on DNA/RNA. He rearranged a patch cilia in single celled forms to be cut out and reversed so the cell swam in circles. This was passed on over countless generations. Prions form a "prima face" case for proteins coding for protein folding information. If a 2nd layer of heritable material exists above the DNA/RNA level then the two systems acting _together_ would provide a _levered_ system of inheritance, i.e. a system where tiny changes provide many different codes only requiring a tiny DNA/RNA base. The blinkered view of gene centric Neo Darwinists that bean bag population genetics can provide all the answers is not credible. Such models are useful but have been painfully misused. RJS:- Or maybe they are, if we can assume that genes are not strictly deterministic. As Venter et al. reported in their genome manuscript: "A single gene may give rise to multiple transcripts, and thus multiple distinct proteins with multiple functions by means of alternative splicing and alternative transcription initiation and termination sites."2 The industry shakeup was predictable. Celera, Human Genome Sciences, and most of the other genomic sequencing firms refocused their business plans and downsized. Venter resigned as president of Celera, and Haseltine has indicated his intention to do the same. LT:- I think Venter and Haseltine were probably kidnapped by aliens or maybe they've been murdered by the Masons. It's certain that there has to be some kind of world-wide conspiracy in order to explain all these strange happenings. JE:- No, just gene centric Neo Darwinistic intransigence. Dr Moran refuses to take a non biased view and allows non testable theory as science to maitain his position. RAGLAND: Perhaps the human genome project hasn't delivered as some thought it would. These things take time. I think there is much that we don't know. Undoubtedly, some of what we think is correct today will have to be revised in the future. The important thing is not to be like the flat earth believers and when science does make new discoveries attempt to suppress it because it doesn't fit our preconceived notions. RJS:- Read the rest at The Scientist http://www.the- scientist.com/yr2004/may/research3_040524.html LU:- The Scientist is not a credible magazine. JE:- Yes, only the non testable dictates of Dr Moran et al are allowed as credible. RAGLAND: LV. Moran can come across as arrogant and belittling but he should, if he cares to, to respond to your accusations against him. |
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Michael Ragland wrote: > > > RJS:- Rethinking Genetic Determinism With only 30,000 > genes, what is it that makes humans human? By Paul H. > Silverman For more than 50 years scientists have operated > under a set of seemingly incontrovertible assumptions > about genes, gene expression, and the consequences > thereof. Their mantra: One gene yields one protein; genes > beget messenger RNA, which in turn begets protein; and > most critically, the gene is deterministic in gene > expression and can therefore predict disease propensities. > > LM:- This is total nonsense. I've been teaching about > genes that don't make mRNA or proteins for 25 years and > I learned about them long before that. > > RJS:- One gene can only yield one polypeptide, but these > polypeptides can be woven into more than just the one > protein. Many proteins commonly constitute one selectable > phenotype, e.g. haemoglobin the red pigment found in the > blood which carries both oxygen and carbon dioxide. Thus > most protein phenotypes are coded for by more than one > gene. Since selection is only possible at the _phenotypic_ > level, mostly, groups of genes are _dependently_ selected > (selected using the same phenotype). Thus, for the > overwhelming majority of genomic genes being "selfish" > cannot pay unless that gene's selfishness is mutual to at > least all the other genes that code for the one phenotype > being selected. > Maybe it is easier to ask: if the genes contribute to a useful phenotype, then how would they avoid being selected? Possibly most easily by not exhibiting fully the mutual selfishness described. It then remains to be shown how otherwise are they selected? > RJK:- Yet during the last five years, data have revealed > inadequacies in this theory. Unsettling results from the > Human Genome Project (HGP) in particular have thrown the > deficiencies into sharp relief. Some genes encode more > than one protein; others don't encode proteins at all. > > LM:- I've also been teaching students about genes that > encode more than one protein for 25 years. JE:- > Incorrect. One gene codes for one polypeptide. As Dr > Moran well knows, a protein is not the same biological > entity as a polypeptide. More than one polypeptide > normally constitutes a protein and mostly, more than > one protein constitutes one selectable phenotype. > To me this is like the gene selecting a program on a washing machine, unaware it is chained to many levels of washing machines all connected together and then asking "is the wash on the right cycle?"! > RAGLAND: The article states, "One gene can only yield one > polypeptide, but these polypeptides can be woven into more > than just the one protein." Is this true? Is the question > one gene can only yield one polypeptide framed incorrectly > in light of genetic epistasis? If genes are not the > causative factor in selecting phenotype then how can we > possibly be able to unravel the secrets of our DNA? Isn't > it likely at least with some genetic diseases the "gene- > centric" model will prove itself? Perhaps some traits are > more epistatic than others. For example, traits such as > aggression and intelligence are arguably epistatic based. > Certainly, it can be argued science will come up with > genetic engineering which will eliminate certain genetic > diseases before we can genetically engineer certain > aspects of intelligence and aggression. > Even in the clear-cut case this may be partly dreaming. For one recessive gene and one dominant, my Punnet square gave ~25% of offspring had traits determined, 75% it was pot- luck (amongst all the combined possibilities). > JE: Gene centric Neo Darwinists prefer to oversimplify > this situation in their attempt to delete epistasis which > is defined as _non_ additive. This just means all the > genes that _must_ be selected _together_ because they code > for the one selectable phenotype. Apparently, these should > not be confused with separate somatic phenotypes which are > regarded as selectively independent, i.e."additive", e.g. > polygenes for human height. That's interesting though because how would that be known at meiosis. Of course it may look like that in a population, but that's like saying because a gas looks continuous there can't be atoms (Brownian motion?). I feel here that must is a little strong an assertion... overall genes would tend to group together but that is why it is selection not determination. > Thus the genes that code for the proteins that constitute > the protein haemoglobin are _dependently_ selected at that > phenotype but the proteins that form the walls of the > artery are supposed to constitute an _independent_ somatic > phenotype. Clearly this is the case re: body phenotypes > but is not the case re: gene fitness because haemoglobin > and the proteins that form an artery wall are FITNESS > DEPENDENT on each other. A good haemoglobin protein in a > blocked artery is selected against because that artery may > reduce the _total_ number of _fertile_ forms reproduced > into _one_ population by the unfortunate Darwinian > selectee who has the faulty artery. A clean artery is > selected against by sickle cell anemia for a similar > reason. In fact ALL then proteins that form one Darwinian > selectee (one fertile form) are FITNESS DEPENDENT. This is > clearly seen when two phenotypes incorporate the same gene > that coded for just the one polypeptide. Here, just that > one gene would be independently selected at TWO separate > phenotypes as well as being dependently selected at two > phenotypes if more than one gene was requited to code for > each independent phenotype. Since the human genome only > has 30,000 or so genes but has millions of heritable and > thus selectable phenotypes, the same genes must be > dependently selected at more than just one phenotype, i.e. > genetic epistasis must dominate entirely, human genetics. > Yet, non epistasis is still regarded as "inherited" but > "not heritable" and thus, "non selectable". > ???? > RAGLAND: You write, "Yet non-epistasis is still regarded > as "inherited" but not "heritable" and thus "non- > selectable". Don't you mean epistasis is still regarded as > inherited but not heritable and thus non-selectable? What > is the difference between inherited and heritable? Isn't > this splitting hairs? > > JE: Like it or not, genomic genes form _dependent_ > selective _webs_ and not just independent selective > chains. The Neo Darwinistic model of independently > selectable genomic genes is not real. Not a single > independently selectable genomic gene has ever been > documented within nature. > Mendel's peas were bred pure first which is almost never the case. Co-dominance and incomplete dominance could occur even for independently selectable genes (and could be important unexpectedly). So even independent selection would not produce definite results in all cases. > RAGLAND: What about the gene for sickle cell anemia? > > > JE: The Neo Darwinian model of independently selectable > genes gave birth to the model that just random events that > change gene freq. of such genes can now be regarded as > "evolution", e.g. genetic drift. They cannot. Such changes > can only be validly regarded as temporal variation. > > RAGLAND: What is the difference between random genetic > drift and temporal variation? > Temporal variation would probably occur naturally and keep a population in a non-equilibrium state (not random, not homogeneous, but ORDERED) that may allow it to adapt more quickly. Random genetic drift (if it is allowed at all, perhaps in the presence of strong mutagens) would confer a poorer ability to adapt unless the population was lucky a) in the degree of drift b) in the particular effects of the drift. > JE: To do so is to _grossly_ misuse an oversimplified > model. A model is not a theory, it is always, a > simplification/over simplification of an existing theory. > Such a model can never be validly used to contest and win > against the theory it was simplified from. To do so is to > turn science into a Mad Hatter's Tea Party. > Yes to the extent that it is impossible to produce anything remotely approaching truly random genetic drift even experimentally never mind theoretically. However a model (even very simplified) that includes "crossover" etc. can be shown to behave in quantifiably different ways to mutate-and-select alone. Such a model can hint (only), however, that a theory may be correct and sometimes models are the best we can do until we have understood more (which the model can help). > RKS:- These findings help refine evolutionary theory by > explaining an explosion of diversity from relatively > little starting material. > > LM:- Really? > > JE:- The argument is that genetic epistasis must provide > the basis for genetic fitness. The gene centric Neo > Darwinistic view that fitness epistasis is "inherited" but > "not heritable" must be discarded. Redefining ftness > epistasis as additive simply deletes all fitness epistasis > and is yet another Mad Hatter solution because not a > single independent in fitness genomic gene has ever been > documented within nature. > If it is essentially deterministic mutate-and-select, models have convinced me nature can do better! Interesting because by making a gross simplification, you can sometimes avoid a grosser one! > RAGLAND" I think sickle cell anemia is an exception. It > conferred protection against malaria. I tend to agree with > what your saying but the reply is "So what"? Science is > currently not advanced enough to understand genetic > epistasis and to be able to influence it. It's much like > my writing about aggression. We know hardly nothing about > its biological underpinnings. Perhaps you are writing to > attempt to create a shift in attitude away from the neo- > Darwinian gene-centric view but I would argue that will > only come when enough scientific discoveries have been > made it discredit it. > > RKS:- We therefore need to rethink our long-held beliefs: > A reevaluation of the genetic determinism doctrine, > coupled with a new systems biology mentality, could help > consolidate and clarify genome-scale data, enabling us > finally to reap the rewards of the genome sequencing > projects. > > LM:- This soounds a lot like new-age doublespeak. Who is > this guy? > > JE:- It is Dr Moran who employs "new-age doublespeak", > i.e. who employs post modern epistemology because he > regards just a random process as being testably causative > to something when it remains impossible to test for such > causation. > Why not put it to the test, then rethink? Race a deterministic genome against a less deterministic one...? (it may involve making a model) > RAGLAND: What are Dr. Moran's views on genetic epistasis > versus neo-Darwinian gene-centrism. Does he take sides or > does he accomodate both views. Can both views be > reconciled with each other? > > JE: At all times, random patterns can validly be supposed > to be caused by _either_ random or non random processes. > Thus the observation of just a random pattern such as a > random genetic drift is NEVER definitive to just a random > process. > > RAGLAND: I think Dr. Moran understands natural selection > and random drift are not necessarily mutually exclusive > processes. > But random drift would certainly NOT map one-to-one onto selected traits, since we don't see random characteristics... So the question really is whether random drift is a good NULL hypothesis even if we don't believe it. And it may well be as good as we can get. However it is difficult to do science with. Beginner. |
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