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Author | Topic: The Nature of Mutations II | |||||||||||||||||||||||
Mammuthus Member (Idle past 6476 days) Posts: 3085 From: Munich, Germany Joined: |
I am highly skeptical that many C's would take the necessary time to reflect on anything scientific such that they would come to such a realization.
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derwood Member (Idle past 1877 days) Posts: 1457 Joined: |
OutOfDate:
quote: I have never said, implied, or indicated that I am an expert in anything. I believe I am more qualified than some in certain areas, true. But I do not believe that I have ever, except perhaps in defense of myself, ever claimed to be an expert i anything, and for you to claim this is a clear misrepresentation. It is alsoi sopmething of a sad joke, for even if I were to make such a claim, it is clear from your writings/rantings that you would be in no position to judge my supposed expertise on pretty much anything.quote: And you have been repeatedly asked to explain what you actually mean by Darwinism, and the one example in which you actually did reply (see the free for all forum), your definition was basically a joke. Not as big of a joke as semi-meiosis, of course, but a joke nbonetheless.But, like I have pointed out several times before, you seem to think that because you have convinced yourself that you are speaking the "truth", it is justified that you denigrate and insult as you do. You claim that you do not insult, but was it not you that claimed that evolutionists are not scientists? quote:So shall we conclude that to you, "Darwinism" means "atheism"? And that it is clear that you are driven not by some desire to learn the reality of evolution, but to prop up some ethereal theistic beliefs of yours? For that is certainly how it comes across.quote:How true. Indeed, as others have mentioned, evolutionists could never get away with what you and your idiot pal Ilion and a few others do there. Terry the simpleton thrives in wirelding his "power" unidirectionally. That is the only way that creationist ideas, like yours, see the light of day. quote: Rivista di Biologica, a formerly respected journal that is now dedicated to publishing fringe quackery. Tell us all, John Davison - as you believe that unless one is doing "wet bench lab work" their conclusions are piffle (i.e., your denigration of "armchair theorists" like Haldane and Kimura) - how much original "wet bench lab work" did you do for this most recent Rivista submission?quote: Actually, one should not ask you questions because you have all the non-answers - "Why, (insert name of dead paleontologiost/fringe scientist here) would agree with me, and (he/she/they) are/were grewat people."Argument via hero worship and denigration of Darwin seems to be the best you can muster, as your semi-meiotic joke is more reliant upon pure chance than is "atheistic Darwinism" and you are too agenda-blinded to recognize it!
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Peter Member (Idle past 1480 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
If they are all directly related to genomic change, and
the only source of heritable genomic change is a germline mutation then I don't see that we need to complicate matters with a billion details. The only way that an offspring can differ genomically fromany possible mixing of it's parents genomes is if the successful germ-cells suffered a DNA copy error when they formed.
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Mammuthus Member (Idle past 6476 days) Posts: 3085 From: Munich, Germany Joined: |
However, by making a distinction between the nature of somatic versus germline mutations i.e. one is a mutation and the other is not according to your definition, one makes things more complicated and certainly less parsimonious if you call the same chemical change something different depending on the cell type.
The second part of your post as I have tried to explain is wrong...individuals can have identical DNA sequence yet one inherits an imprinting mutation which is not a DNA copy error. Different enyzmes replicate DNA and methylate it. Both are capable of making errors leading to mutation.
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Peter Member (Idle past 1480 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
For the first part, I've not (intentionally) been saying that
a somatic mutation shouldn't be a mutation only that it should be made clear the mutations are [oops] not all there is to heritable change. The second part was what I thought you were telling me, then Ithought it wasn't, now I KNOW it is what you are telling me What is the exact nature and origin of the 'imprinter'? Do you mean there is an enzyme for replication and another formethylation? [This message has been edited by Peter, 07-08-2003]
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Mammuthus Member (Idle past 6476 days) Posts: 3085 From: Munich, Germany Joined: |
I think when you say somatic mutation versus germline mutation that makes it pretty clear which can be inherited.
quote: I think this was my exact response when salty first brought up semi-meiosis Imprinting is not very well understood i.e. how it is regulated. Bioessays. 2003 Jun;25(6):577-88. Related Articles, Links Imprinting evolution and the price of silence. Murphy SK, Jirtle RL. Department of Radiation Oncology, Duke University Medical Center, Durham. In contrast to the biallelic expression of most genes, expression of genes subject to genomic imprinting is monoallelic and based on the sex of the transmitting parent. Possession of only a single active allele can lead to deleterious health consequences in humans. Aberrant expression of imprinted genes, through either genetic or epigenetic alterations, can result in developmental failures, neurodevelopmental and neurobehavioral disorders and cancer. The evolutionary emergence of imprinting occurred in a common ancestor to viviparous mammals after divergence from the egg-laying monotremes. Current evidence indicates that imprinting regulation in metatherian mammals differs from that in eutherian mammals. This suggests that imprinting mechanisms are evolving from those that were established 150 million years ago. Therefore, comparing genomic sequence of imprinted domains from marsupials and eutherians with those of orthologous regions in monotremes offers a potentially powerful bioinformatics approach for identifying novel imprinted genes and their regulatory elements. Such comparative studies will also further our understanding of the molecular evolution and phylogenetic distribution of imprinted genes. BioEssays 25:577-588, 2003. Copyright 2003 Wiley Periodicals, Inc. ...but DNA is replicated by DNA polymerases..DNA is methylated by DNA methyltransferases.
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
There are several enzymes for methylation. There are enzymes both to add and remove methylation form CpG sites. The methylation patterns in an organism are highly dynamic.
Imprinting is a seperate but related phenomenon found in mammals and plants. In imprinting the methylation pattern differs between the maternal and paternal genetic contributions. This pattern is maintained when most other zygotic methylation patterns are reset, although the exact dynamics vary from species to species.
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Peter Member (Idle past 1480 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
So do a cell's methylation enzymes come from the 'parent'
cell or are they produced within the cell?
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Peter Member (Idle past 1480 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
If the methyltransferases are passed into the 'new' cell
from the 'parent' cell (as opposed to be produced in-cell), but were incorrectly produced within the 'parent' cell ... I'd call that a 'protein synthesis error' (assuming it is OK to refer to the ...ases as proteins). That would give two sources of heritable mutation ... onein the genome (a germline mutation) and the other in the regulatory system (a protein synthesis error).
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Wounded King Member Posts: 4149 From: Cincinnati, Ohio, USA Joined: |
The methyltransferases are produced in the zygote, but the imprinted patterns are established in the sperm and egg.
It seems very wide of the mark to call this a protein synthesis error. The problem is not one of a mutant form of protein being produced, due to an error in protein synthesis, although constitutively active forms of methyltransferase can be produced. The point is that DNA methylation is, in the normal way of things, dynamic. And as with most things in biology, it largely depends upon stochastic events. Consequently even with all the enzymes in a cell functioning as expected environmental factors and chance can give rise to atypical patterns of methylation which can, in certain circumstances, lead to a heritable phenotype.
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John A. Davison  Inactive Member |
Scott has lost none of his charm, For what it is worth, ISCID is publishing the Manifesto in its online journal. I'm sure Scott can find plenty to ridicule about that as well. Go for it Scott. It is music to my AntiDarwinian ears. salty
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wj Inactive Member |
Salty, you have failed to respond to Schrafinator's question:
quote:-------------------------------------------------------------------------------- So, how do we tell the difference between an Intelligently Designed system and one that we do not currently understand or one that we do not have the intelligence to ever understand? -------------------------------------------------------------------------------- The question is fundamental to your assertion that "I do not understand Intelligent Design but that it exists is beyond any doubt." You need to provide evidence such as examples of intelligent design and why intelligent design is a better explanation for the example than the conventional scientific explanation.
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Mammuthus Member (Idle past 6476 days) Posts: 3085 From: Munich, Germany Joined: |
yeah..what Wounded King said
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Mammuthus Member (Idle past 6476 days) Posts: 3085 From: Munich, Germany Joined: |
Are you going to post anything substantive or answer any of the multiple questions addressed to you or are you going to obsess about Scott for the rest of your stay here?
cheers,M
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Peter Member (Idle past 1480 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
...so even with the methylation states the same as the
parents the phenotype can be different?
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