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Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
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Author | Topic: Information and Genetics | ||||||||||||||||||||||
Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
This seems to be a major topic, so I thought I'd
pop a thread up on it. If there already is one, apologies and point me to it I've seen a lot of claims that information theory can be used to refute ToE, and would like to know why. I'm not going to belabour the issue of defining information ...well not to start with ... but want to question the principle of applying information theory to genetics. Is there any information content in an organism's genetics ? We use the analogy of a genetic code, but is it actuallya code ?
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Pedantic bit:: A computer is not an intelligent device, it is adeterministic, electronic 'machine'. Check the definition of intelligence that you provide if you don't believe me. You assert that a change to an existing 'algorithm' isn'tnew information (in the sense that you define info.). What if successive small changes to an algorithm ultimatelyproduce an algorithm that's function is radically different from the start-point ? Is that still not new information ? To attempt an analogy using words:: If we start with 'cat' and modify one letter to make 'bat'is the information conveyed by the second word (to an english speaking individual) new or not ? It's just a modification, but once 'interpreted' to provideinformation within the recipient isn't it new information ?
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: The point I was trying to make is also relate to ::
quote: Which is at the hub of the whole question of 'information' let aloneinformation in a bilogical context. The sub-routine with a bug has a functionally different outputto that intended (otherwise there wouldn't be a bug) so it contains a 'new' algorithm compared to that originally envisaged. 'Information' cannot be transmitted at all, only data can. And there IS a difference between data and information (whichdistinction, incidentally, Shannon (nor any other communications experts of the past) ever explicitly make). In my word analogy it doesn't actually matter what I intended toconvey by putting 'bat' on the page ... the fact is that any english speaking individual on reading that word will flash mental images through their mind of baseball bats, cricket bats, fruit bats, vampire bats, or what-have-you. Information is ONLY formed in the conscious mind of the individual observing the data, and is highly context and historically sensitive. So now we have the problem that I see with applying the term'information' to biology. Information is something that a 'viewer' obtains from data, whetheror not that data was intended to hold that 'information'. Saying that the change from 'cat' to 'bat' is a loss of informationpre-supposes that I originally intended to convey 'cat'. In the biological/genetic sense this is to start with the assumption that there IS a creator of genetic code, and that that data was intended to contain/convey some kind of 'information'. This is why a large part of my question here is 'Does the geneticcontent of a cell convey information ?' If so, what form does that information take ? Since information can only be derived from a subjectiveviewing of data, is it even relevent to biological systems in the context of evolution/creation hypotheses ?
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: How do you detect design ? I thought IC was put forward as anevidence of design, but I don't find it compelling. Effectively the argument of IC is one of incredulity. That issince we cannot imagine a way that such a thing could have evolved then it can't have. quote: Two things about the above ... the unless part defines thenot explained now part so I don't see what you are driving at. As far as left-handedness is concerned check outthe 2001 Nobel prize for chemistry:: http://www.nobel.se/chemistry/laureates/2001/public.html The background to which points out that :: "In the early sixties it was not known whether catalytic asymmetric hydrogenation was feasible, i.e. would it be possible to catalyse an asymmetric reaction to produce an excess of one of the enantiomers? The breakthrough came in 1968 when William S. Knowles was working at the Monsanto Company, St Louis, USA. He discovered that it was possible to use a transition metal to produce a chiral catalyst that could transfer chirality to a non-chiral substrate and get a chiralproduct. The reaction was a hydrogenation in which the hydrogen atoms in H2 are added to the carbons in a double bond. A single catalyst molecule can produce millions of molecules of the desired enantiomer. " So the potential existence of catalysts that will produce thiseffect has been known for over thirty years ... if they can exist in a lab isn't it at least possible that they could have existed on earth billions of years ago ... after all none of us know exactly what the conditions were when life began to emerge. The possibility of a catalyst being responsible is quite telling I feel. We don't even have to mention that cosmic radiation can promoteone handedness to dominate ... oh I just did
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: (a):: Well, yes, but for life to form spontaneously the conditionswould have had to be 'just right' ... the possibility of a chemical precedent for the dominance of one-handedness is a first step in placing reasonable doubt on chirality as a bar to the naturalistic emergence of life. (b):: But the catalysts are much more simple than amino-acids,and could perhaps emerge naturally. (c):: I think they use this process to make menthol.
quote: My understanding of 'Transition Metal' is the bunch of chemicalelements in the middle of the periodic table ... in which case they can occur naturally. Even if they are rare now, that doesn't mean they have always been rare ... it's unknowable, but adds to the reasonable doubt (over this one issue). quote: I thought there were some Right handed proteins in somebacterial cells ... might be wrong about that as I'm dredging up memories from a debate on this issue I had about two years ago ... I've got some e-mails stored somewhere Anyhow ... that is a problem, but then a part of the anti-abiogenesisargument is that amino-acids wouldn't even survive that long. So perhaps we have localised conditions were we generate amdmaintain a left-handed dominance. The catalysts I pointed out would allow this if we can find another set of conditions that allows amino-acid survival and combination into peptides. [b] [QUOTE]
Secondly, the amino acids that they manage to get to be L-forms don't just 'get together'. All of these products have a specific amino acid sequences. The scientists have to acquire L-forms by using synthetic catalysts, and then put the amino acids in the right order to form the right substance. About half of the amino acid sites are called active sites, at which a wrong amino acid could be fatal (take sickle-cell anemia for an example). Did I mention that peptide and non-peptide bonds occur at roughly equal frequency in nautre, as well? You also have to get all of the amino acids to form peptide bonds with each other.[/b][/QUOTE] I think that's jumping ahead (unless I mis-understand) to DNAisn't it ? Your talking about 'fatality' while I'm just discussing prdocutionof proteins structurally similar to those required for life as we know it. quote: What year was Behe's book ? I read about some Japanese research in a news article two yearsago that said that they had found poly-peptides forming around deep sea thermal vents. The vents act as a kind of poly-peptide factory where some amino-acids join in the vent, come out on currents, and are fed back into the system. I'll try to dig out anything on that too.
quote: How deep into water can UV penetrate ? I seem to remember thatit's not far, but I could be wrong. [Hope you have/had a nice trip ] [This message has been edited by Peter, 07-23-2002]
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: I think I must have mis-understood the context in which youraised the issue. quote: The article makes four points:: 1) It questions the starting/environmental assumptions made.This seems to be pot calling kettle black to me. What were the exact conditions on Earth at the time of the emergence of the first amino-acids. Niether of us know so this objection seems contrived. 2) Raises temperature objection ... when the research itself suggestsa 'quenching' effect to combat this. And then mentions chirality. ... which is kinda what we were talking about anyhow so I'll come back to that. 3) Seems a little odd. In a limited experiment don't you expectlimited, but indicative results ? Perhaps the claims that this IS how it all started are overstated but to say that it is categorically not the way it happened based upon one small-scale experiment is equally dogmatic. My feeling is that it lends credibility to the potential fornaturalistic formation of the first amino-acids, and possibly proteins. 4) Pretty much as above. I don't claim to have the answer (I'd certainly be up fora Nobel prize if I did ) but the refutation article appears to me (as a trained researcher) to be a knee-jerk, assuming invalidity style of article. It has not critiqued the methods and conclusions from an impartial stand-point, but sought problems because the position is contrary to those held by the author. Inevitably some of the raised objections are not really relevant. quote: Transition metals are just elements, and they occur in nature(otherwise we wouldn't know about them ... i.e. they are not transuranic elements manufactured via 'atomic' processing). The catalysts are relatively simple ... and perhaps are notthe oly chiral catalysts possible. One molecule of catalysts can produce millions of molecules with a chiral imbalance. How does that complicated matters. If producing a simplemolecule can increase the yield of the right kind of more complex molecules doesn't that help ? Always wondered about this chirality issue in any case ...R- and S-Limonene are lemon and orange smells ... doesn't that mean that either the orange or the lemon has a left-handed protein that works fine ? And don't some bacteria have left-handers in their cell membranes ? We don't appear to need ALL r-handed, only a tendancy for R-handed. The possibility of catalysing such a dominance surely has a littlebearing. quote: EO - 404 Error I found the above, which, even discounting the organic carbonimpurities, suggests that UV-B (at least) is rapidly disapated in water. So if the amino-acids were at deep-sea location, that wouldnot be such a bar to production I guess. quote: No problem, I've been a bit busy myself.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
[QUOTE]Originally posted by John:
[B][QUOTE]Originally posted by Peter: [B][QUOTE]I found the above, which, even discounting the organic carbon impurities, suggests that UV-B (at least) is rapidly disapated in water. So if the amino-acids were at deep-sea location, that wouldnot be such a bar to production I guess. [/b][/quote] Lipid molecules, major players in the abiogenesis debate, would float on the surface.[/B][/QUOTE] Oh. What if it was all sparked off by an asteroid impact ? Sudden random thought I know, but the collection of thoughts leadingup to the wondering is:: Some scientists postulate that organic compounds could surviveon asteroids enetering earth atmosphere. Cosmic radiation can affect the distributions of enatiomers A dust cloud resulting from a large enough asteroid collision couldproduce particles in the atmosphere which would dissipate UV radiation It is considered that in the early life of the solar system such impacts were not that rare. Could provoke siesmic activity resulting in heat release frommantle (energy source). ---------> Just a thought ....
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
...but could the high presence of incoming rocks
have promoted an atmosphere much different to today which would block UV for extended periods. As I understand current thinking it is considered thatmany (varying sized) asteroid impacts happened in the early life of the earth.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
... but is there actually any information content
of DNA, or is it just the way we view it?
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
But with a hard-disk we start with the assumption that
the data on it was put there by someone ... and the binary digits stored are data not information. The main reason that I started this thread was to discuss the line of reasoning put forward by some YEC's that the informationcontent of DNA is an indication of design. DNA contains sequences that are used in the cell to createproteins etc. and that process in itself is pretty complex, but does DNA actually, objectively contain information (can you even have objective information?) ? The issue of information and genetics is important in theconsideration of design ... but is extremely complex, compounded by the abstract nature of information. Another contention, within the context of the information = designline of reasoning, is that information has to come from an intelligent source. Is this true? If I write a computer program to randomly generate a three lettersequence, and eventually that comes up with 'cat', and english reading individual will read that sequence and glean information from it ... it is related to all things feline in the consciousness of the observer. There is no intelligence behind the emergence of the sequenceabove, the intelligence is in the observer, who assigns meaning to it, and thus forms information.
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
If I have a group of chemicals and I put them together
in a flask, give 'em a whisk, add some heat energy maybe, and they react to form something else ... does that mean that the starting molecules contained the information required to perform the reaction? |
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: Evolution DOES move uphill on the fitness terrain -- thatdoesn't mean that things have to go from simple to complex. It means they have to tend toward the more suitable wrt theselection criteria. If there was any merit to the line of reasoning you seem to beimplying (that evo. requires movement toward the complex) then surely there would be no single-celled critters on earth. Haven't amoeba been evolving for billions of years too? (withinthe evolutionary framework that is ... not in your opinion) [This message has been edited by Peter, 09-16-2003]
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Peter Member (Idle past 1509 days) Posts: 2161 From: Cambridgeshire, UK. Joined: |
quote: In what way is the frequency of use of such techniques relevant tothe discussion of whether or not they can illuminate the issue of natural processes being capable of design? quote: In no particular order: Re (2): Mutations are allowed, they are random ... that some helpto progress toward an acceptable solution suggests that mutation can lead to design-like qualities (when coupled with selection). In EA's the mutations are not directed, they are simply governedby 'natural' laws and minimal components. Re (3): How do you develop a solution with a EA without rejectingsome 'results' completely? That is extinction. Re (4): Depending on your definition. The selection criteria arejust that something to compare outputs to ... that's what natural selection is saying -- the outputs tend toward a fit with the environmental conditions. Re (1): Eh? EA's use the supposed mechanism of evolution, but actupon different components. The results are designs which were not generated by an 'intelligence' but by a mechanistic process
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