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Author Topic:   Devolution (from The Fall) and "No New Information"
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 14 of 52 (518412)
08-05-2009 10:51 PM
Reply to: Message 12 by New Cat's Eye
08-05-2009 2:10 PM


They don't say that. They are just examples of neutral and deleterious mutations
I just wanted to precise that there is a difference (a very important one) between neutral and nearly-neutral mutations.

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 Message 12 by New Cat's Eye, posted 08-05-2009 2:10 PM New Cat's Eye has replied

Replies to this message:
 Message 17 by New Cat's Eye, posted 08-06-2009 9:23 AM slevesque has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 15 of 52 (518420)
08-06-2009 12:30 AM
Reply to: Message 1 by Coyote
08-03-2009 11:05 PM


Ok, I'll give it a shot
I'll start with a little anecdote that I find related to what you are asking. Here in Quebec, we have a TV program called 'Infoman' which is a humoristic show about what is making the News, especially on the politics side. Now about a year ago, there was this controversy about the Canadian minister of Science about if he believed in Evolution or not; He had not responded a question about this invoking 'personnal reasons'. This was the first time in about ten years that there was a controversy on the subject of evolution in Quebec, and so Infoman decided to go to a creationist conference that was held by some unknown guy with no education in science.
Of course, the point of it all was to make fun of it all, and sure enough he found a poor little grandmother who provided him with extremely funny quotes. There was one in particular which caught my attention: ''You start off in life as a little baby, all cute and beautiful. But as time goes by, you get older and uglier. So you can't go from a monkey and end up with a human''
Although her statement was extremely fallacious (she had to be over 80 years old lol) I do find it somehow relevant in this discussion. There are things in nature which seem to say everything is going downhill. Of course, the process of aging is one of them, because as you get older, you not only get uglier haha but you also become less capable, always on a downhill until you die.
This can also be seen in nature. Things break down, continuously. Walls will fall down with time, as will the pyramids eventually disappear (given a couple thousand years). Rocks become dust. etc. And so I do think that, even without any religious concept of 'the fall', this idea that everything tends to go downhill and break down in nature would have been proposed in the history of science.
Also, recently, in the last 100 years or so, the vast domain of informatics and programming has been established. Yet every experience of programming codes in this area has always showed the same conclusion: that a code will eventually break down, even with the most sophisticated error-correcting mechanism. The advent of informatics would have also pushed the idea that codes (including DNA) go 'downhill' even in a hypothetical world without the religious notion of 'The Fall'.
--
Now, as far as I am concerned, the real question is not 'Can information-adding mutations happen ?(theoretically they can)'.
Knowing that the DNA code, if left replicating on its own, will break down and go 'downhill', it is rather 'Can natural selection effectively turn that tedency from downhill to uphill?
PS This last part may be off-topic, if Coyote judges it to be so I'll take it away.

This message is a reply to:
 Message 1 by Coyote, posted 08-03-2009 11:05 PM Coyote has not replied

Replies to this message:
 Message 16 by Theodoric, posted 08-06-2009 8:40 AM slevesque has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 39 of 52 (518871)
08-09-2009 1:44 AM
Reply to: Message 16 by Theodoric
08-06-2009 8:40 AM


This is fallacious on the face of it. Are you saying that a 3 year old has gone downhill form a newborn? How do you define downhill?
I was answering Coyote opriginal question as I understood it: How could the concept that nature is on a downhill path have arisen in a hypothetical world that did not have christianism. In other words, could you have this impression by looking at nature ?
Evidence please and again define downhill.
I hope my next reply will clarify this a bit.

This message is a reply to:
 Message 16 by Theodoric, posted 08-06-2009 8:40 AM Theodoric has replied

Replies to this message:
 Message 40 by Theodoric, posted 08-09-2009 1:53 AM slevesque has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 41 of 52 (518875)
08-09-2009 2:36 AM
Reply to: Message 17 by New Cat's Eye
08-06-2009 9:23 AM


Like how?
I'd determine the neutrality of a mutation by whether or not the environment selectively pressures it and since, when you get down to the gnat's ass, its going to be so blurry that you can't really tell if there's pressure on every particular mutation or not then I'd claim that you are unable to tell if mutations really are neutral or not in every case. Maybe in some specific cases, but I don't see where you're going to define this very important difference between neutral and non-neutral. And I don't see how its important at all unless you want to disbelieve in evolution.
Of course, I do not want to 'believe' or 'disbelieve' anything, but I do want to test such an important scientific theory as Neo-Darwinism, and I'm pretty sure you don't have anything against that.
Now, on the neutrality of a mutation. This is the definition from wikipedia:
quote:
In genetics, a neutral mutation is a mutation that occurs in an amino acid codon (presumably within an mRNA molecule) which results in the use of a different (but often chemically similar) amino acid that has a negligible effect on fitness
The important word is 'negligible'; it means that the mutation does have an effect, but it is so small that it cannot be detected by natural selection. An analogy could be if an atom on my car 'rusts', it will not have any impact on the performance of my car, but that will not mean that it is 'neutral'. An atom rusting will be deletirious even if it as no effect on the overall performance.
In genetics, a neutral mutation does not exist, but the majority of mutations are nearly-neutral.
Now this difference between a totally-neutral mutation and a nearly-neutral mutation has always been assumed as not important in population genetics, and so they have been redefined as effectively neutral. In other words they are considered as neutral when doing the calculations and the simulations. (This is in fact what Kimura proposed in his neutral theory of molecular evolution)
But as the car-rusting analogy shows more clearly, the accumulation of rusted-atoms on the car will eventually lead it to break down. Nearly-neutral mutation accumulation will eventually lead the genome to genetic meltdown.
quote:
And there are things in nature that prove that not everything is going downhill.
For the first 18 or so years of our lives we are going uphill. When a snowflake forms or when salt crystals grow. When populations evolve.
Of course, I agree (accept for, of course, that last example ). See my previous post for clarification of what I was trying to say.
I don't believe you.
Well the DNA code without natural selection filtering deletirious mutations will eventually become meaningless because of mutation.
Introducing random variations in a Code will always make it lose its meaning. Sure you might get a new 'word' here and there, but overall and on the long term, the message will be lost. Same with DNA without natural selection.
We can easily see that this is a big YES by taking a trip to the zoo and seeing the variety in the species that has evolved.
This is only true if you presuppose that these species have evolved. Only then can you see it as proof that Neo-Darwinian evolution can create the diversity you see.
Also, you're answer was very superficial in its nature. An answer to the question I asked woiuld recquire an in-depth look at the selection capcity of a population, the selection cost of mutations, etc.
So yeah, genes can add new information.
I do think that you meant 'mutations' here instead of 'genes'. Anyhow, saying that beneficial mutations can happen will not answer the question I asked (Which was about the capacity of natural selection to reverse the natural tedency of the DNA code which is to go downhill)
--
Yheodoric asked me to define what I meant by downhill. To make it simple, a downhill trend in a biological population would be to gradually lose fitness.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 42 of 52 (518877)
08-09-2009 2:43 AM
Reply to: Message 40 by Theodoric
08-09-2009 1:53 AM


I don't know how I can be clearer on what was my intentions in my first post ...
But I will answer your question:
Are you saying that a 3 year old has gone downhill form a newborn? How do you define downhill?
As soon as the very first cell starts to replicate, mutations start to accumulate. And since it is an asexual reproduction, Muller's ratchet applies and so these mutations acumulate. So genetically speaking, a 3 year old DNA has gone downhill since it was born.
The definition of dowhill is in my previous post.

This message is a reply to:
 Message 40 by Theodoric, posted 08-09-2009 1:53 AM Theodoric has replied

Replies to this message:
 Message 43 by Theodoric, posted 08-09-2009 9:23 AM slevesque has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 44 of 52 (518948)
08-10-2009 1:32 AM
Reply to: Message 43 by Theodoric
08-09-2009 9:23 AM


No this is genetics. Cellular reproduction is asexual, and so Muller's ratchet applies.
The accumulation of mutations in our cells as they replicate and we grow up is what ultimately causes us to die, the software of our cells becoems so corrupted by mutations that systems and organs start to fail, etc. etc. This process starts from the very first replication of the very first cell, not just from after 3 or 18 years of age.
Edited by slevesque, : No reason given.

This message is a reply to:
 Message 43 by Theodoric, posted 08-09-2009 9:23 AM Theodoric has replied

Replies to this message:
 Message 45 by Meddle, posted 08-10-2009 3:23 AM slevesque has replied
 Message 47 by Theodoric, posted 08-10-2009 7:58 AM slevesque has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 46 of 52 (518956)
08-10-2009 3:40 AM
Reply to: Message 45 by Meddle
08-10-2009 3:23 AM


Of course, I did not to make it seem as though we die becuase of one reason. It has multiple factors. Still, mutations accumulate as we grow older from the very first cell.
Well our chromosomes have two copies, which means mutations can be eliminated during mitosis as the chromosomes cross over, negating the effects of Muller's ratchet. Unlike bacteria for example, where only one copy of the genome exists
Mutation are not really eliminated, since one of the daughter cells will always end up with the mutations that the initial cell had. Because, all in all, all the chromosomes will end up in one of the two cells.

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slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 48 of 52 (519021)
08-10-2009 3:08 PM
Reply to: Message 47 by Theodoric
08-10-2009 7:58 AM


Of course, I mentioned that genetically speaking, it has gone downhill. The DNA message with the acumulation of mutation, loses its meaning and so eventually becomes 'incomprehensible' for the cells as we get older.
Genetically speaking, this is not a subjective statement.

This message is a reply to:
 Message 47 by Theodoric, posted 08-10-2009 7:58 AM Theodoric has replied

Replies to this message:
 Message 49 by Theodoric, posted 08-10-2009 3:18 PM slevesque has not replied
 Message 50 by Wounded King, posted 08-11-2009 4:51 AM slevesque has replied

  
slevesque
Member (Idle past 4640 days)
Posts: 1456
Joined: 05-14-2009


Message 51 of 52 (519103)
08-11-2009 10:38 AM
Reply to: Message 50 by Wounded King
08-11-2009 4:51 AM


Of course, I'm not an expert on this subject, and I know that the process of aging is not well understood even today.
As I've also said in another post, I do not intend to make the process of aging and death a simplistic one with only a single factor. Multiple things come into play and eventually the effects add-on to bring the organism to be unable to maintain it's activity any longer.
I did not intend this as a model of aging, but only a model of one of the factors of aging.
As you and others have mentioned, there are mechanism in the body who prevent as much as possible the accumulation of mutations as we grow older (controlled death, etc.). These would be analog to some sort of 'natural selection' inside the body.
The 'inbuild limitation of cellular replication' is aso interesting, although I have not much knowledge on it. But I would wonder why such a mechanism would even develop in evolution. In oher words, what is the evolutionnary advantage of it if its main purpose is to limit our cellular replication and make us die ?
Also, I would also think that stem cells are not exempt of mutation accumulations as we grow older, which would lead to the breakdown you mentioned, I have no idea of how stem cells replicate and if they do in an asexual manner (well, probably I would guess), so maybe they can avoid mutation accumulation.
Finally, this is not my field of expertise in french, let alone in english, So my knowledge as well as my vocabulary is limited and I would like you to consider this when replying on this subject.

This message is a reply to:
 Message 50 by Wounded King, posted 08-11-2009 4:51 AM Wounded King has replied

Replies to this message:
 Message 52 by Wounded King, posted 08-12-2009 5:24 AM slevesque has not replied

  
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