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Member (Idle past 4869 days) Posts: 624 From: Pittsburgh, PA, USA Joined: |
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Author | Topic: Jerry's Calculation of Entropy in Genome | |||||||||||||||||||
JustinC Member (Idle past 4869 days) Posts: 624 From: Pittsburgh, PA, USA Joined: |
I've been away from the computer for a while, and sadly the topic where Jerry and I were discussing his calculation was closed. The conversation was getting a bit messy anyway, so I would just like to comment on your calculation one more time and get a response. The original conversation started with this message:
http://EvC Forum: Intelligent Design in Universities -->EvC Forum: Intelligent Design in Universities The calculation was
quote:Jerry is putting nucleotides into two categories for this calculation, ancestral and deleteriously mutated. After this, he uses the equation (N1+N2)!/(N1!N2!) to calculate the supposed gain in entropy of the genome after one generation of deleterious mutations using the Eyre-Walker results of 1.6 per generation. So here's my counter, using a Reductio Ad Adsurdum type argument. It's very simple. Jerry supposes the entropy will go up from some ideal ancestral state, and this will be correlated with an information loss. He uses the calculation above. N1 will represent ancestral nucleotides, N2 will represent deleteriously mutated nucleotides. The original entropy, before the mutations, is: (N1+0)!/(N1!0!)=1 After one round of mutations: (N1+N2)!(N1!N2)!> 1 Eventually, we'll reach a point where we have more deleterious mutations than we have ancestral nucleotides. After this, entropy will begin to decrease. So, the more deleterious mutations that accumlate after that point, the more the entropy will decrease until it reaches 1 again. This goes against the original statement that "an increase in entropy is correlated with a loss of information", since now a decrease in entropy will be correlated with a loss of information. It also goes against the notion that entropy is measure of disorder, since as disorder goes up (in the sense that information is being lost) entropy decreases. This seems absurd. I would like to remind Jerry that entropy is a state function, and doesn't depend on the path taken to get that particular state. So replying that an organism will be extinct by the time the mutations reach that level is not a counterargument. It's also way off target since we are not talking about an organism but the entropy associated with the genome. The fate of the organism after the change in the genome isn't relevant. So to summarize, if I have understood the calculation, it seems that a decrease in information can result in a decrease in entropy (not an increase). Anyone is welcome to comment, especially if they see an error in my reasoning. This message has been edited by JustinC, 05-12-2005 06:53 PM
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JustinC Member (Idle past 4869 days) Posts: 624 From: Pittsburgh, PA, USA Joined: |
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JustinC Member (Idle past 4869 days) Posts: 624 From: Pittsburgh, PA, USA Joined: |
quote:I honestly have a hard time following this. I'll just calculate W since it is directly proportional to entropy. Also, I know I was only calculating W, not delta W. But, delta W could be found by comparing the different generations. Here is the calculation again. I will assume ancestral nucleotides to begin with. We start off with a W of: 1. (1000!)/[(1000!)(0!)]=1 After I mutate a quarter of the nucleotides to deleteriously affect some genes: 2.) (1000!)/[(750!)(250!)]>1 After I mutate half of the nuceotides: 3.) (1000!)/[(500!)(500!)] >>1 After I mutate all of the nucleotides, so no information is left in the 1000 nucleotide segment: 4.) (1000!)/[(0!)(1000!)]=1 As you can see, the change in entropy is always positive except for the last change, from (3) to (4), which is: 5.) Delta W= (1-(>>1))= - N I apologize for the abbreviations since I don't have a calculator handy, but you should get the point. According to your calculations, if I take a one thousand nucleotide DNA sequence full of genes, and then mutate every nucleotide to deleteriously affect the gene products, then the entropy remains the same. Or, to put it another way, a one thousand nucleotide DNA sequence with half of the nucleotides deleteriously mutated will have a higher entropy than the same sequence with all the nucleotides mutated. The change would be negative if going from the former to the latter using your equation.
quote:I'm just using the equations you used to show an absurditiy. That should communicate to you that your equations aren't sound. Please show me exactly where my calculation is in error. This message has been edited by JustinC, 05-14-2005 08:40 PM
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JustinC Member (Idle past 4869 days) Posts: 624 From: Pittsburgh, PA, USA Joined: |
quote:It doesn't matter if I use W or S, or Delta W or Delta S, W and S are directly proportional. All I would be doing is taking the ln of the of the number and multiplying it by a constant. You can do the extra math if you want, but the results will turn out the same. quote:Yes, I know I am using W. They are directly proportional. Do the extra math if you would like, the answer will be the same. For instance, look at my last generation, with all the nucleotides deleteriously mutated: W= (1000!)/(0!)(1000!)=1 S= k ln W= 0 So delta S going from equation (3) to (4) would be: Delta S= Sf-Si= 0-(k ln (>>1))=-N That final entropy would be zero, the entropy before that would be a positive number, giving a negative delta S. A decrease in entropy as more deleteriously mutations accumulate.
quote:You were the one trying to equate information loss (in the sense of changing the ancestral state of the genome) with entropy increase. You used that equation to show it. I used that equation to show an absurdity, which (if correct) calls into question your whole calculation. Go from (3) to (4) in my calculation, calculate S's for both, and then find delta S. It will be a decrease in entropy as more deleterious mutations occur. quote:I don't see what's so hard to understand. I am increasing y, i.e., mutating more than half of the genes. When I do this, your equation says the entropy will decrease. This calls into question your calculation, since I don't think you want to be saying this. quote:I did above, but I'll do it again for the hell of it. Equation (4) says W=1, so the entropy will be: Sf= k ln 1= 0 Equation (3) says the entropy is more than 0 (I'll use W=1.3 as an example), so: Si= k ln (1.3)>0 So Delta S, going from (3) to (4), would be: Delta S= Sf-Si= 0- (>0)= -N. It will be negative still.
quote:I have absolutely no idea what that is supposed to show. We are talking about the entropy of a genome if we dichotomize into ancestral and deleteriously mutated nucleotides, using the equation for statistical weight (N1+N2)!/ ((N1!)(N2!)). What does the generation of the organism have to do with that, and how would that factor into the calculation. The only way I can see it factoring into the equation would be if we write the number of deleterious mutations as a function of the generation. The result will be the same, once we get to a certain point the more delteriously mutations that accumulate the entropy will decrease.
quote:The formula should be consistent with the point you are trying to prove. You are trying to prove that deleterious mutations in the genome constitute and increase in entropy. You equation says it does this to a point, and then the entropy will decrease. quote:I don't. Calculate the entropies. Entropy will decrease after a certain point as more deleterious mutations accumulate. The reason I am going through the trouble of this is because I think you just pulled that equation of the internet and tried to use it without understanding it. It works great with the gas in a box, but you can't just extrapolate it to any binary system, as PaulK was saying
quote: That's the crux. This message has been edited by JustinC, 05-17-2005 07:45 PM
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