How does DNA maintain order over time?

[precisionart]

It seems that dna is constantly taking on damage - entropy. Why doesn't this damage accumulate over time? It appears that the amount of genetic damage that should accumulate would significantly outweigh the amount of ordering produced from the basic mechanisms of evolution. How is DNA ordering sustained over time? Is there a process of 'healing' or re-ording?

 

[Pythagorean]

one example:

http://en.wikipedia.org/wiki/Telomere

 

[Ryan_m_b]

There are many, many processes across different species involved in DNA repair
http://www.nature.com/scitable/topicpage/dna-damage-repair-mechanisms-for-maintaining-dna-344

 

[phyzguy]

However, even without DNA repair, natural selection will weed out the errors. If an error makes the organism non-viable, it dies and that error is not passed on. Errors with no consequence (such as base pair substitution that results in the same amino acid) do accumulate over time, and scientists use this fact to deduce the time between species divergences. See:

http://en.wikipedia.org/wiki/Molecular_clock

 

[castro94]

entropy is the particle`s tendency to go from order to diorder. Entropy is directly conected with kinectic energy. a particel at the absolute zero will have lost its tendency to go from order to disorder , because it can't move any more , in the same way the higher the temperature is the more energy the particle has , the more it moves and the higher the porbaility for it to move over to disorder.
Living organism differs from inanimate "things " in its ability to take order from its surronder to "take" away the entropy it has gained by nature. This ability is simply our metabolism , the air and the food we take from our surronder is transformed to "negative entrophy" that is then used to "take out " the possitiv entropy ( positive entropy is disorder while negactive is order ). so this process cleans all the organism from the "entropy damage "
Mutation in Dna are a discontinuos rearengement of the atoms in the molecules inside the
DNA caused by the heat motion of particlees around it , therefore it can be called "entropy damage" this cannot be repaired .
But not alll the "entropy damage " can be repaired , this is why we die basically.
sceintists are currently researching for methods to help the cleaning process , this will eventually make us immortals :)

 

[Ryan_m_b]

But not alll the "entropy damage " can be repaired , this is why we die basically.
sceintists are currently researching for methods to help the cleaning process , this will eventually make us immortals :)

I assume you mean why we age rather than why we die and as far as I am aware DNA damage is not the only cause of aging. There are a whole host of epigenetic factors that come into play.

Finally let's keep the conversation within the rules. Baseless speculation regarding immortality is not productive.

 

[castro94]

dead is the entropy equilibrium , the point of maximum entropy . this can only be reached when the organism is no longer able to "clean " itself . i agree with you that it can be regarded as the cause of aging , because aging will eventually lead to death. as aging is the degradation of the body , and death its final point .
I did not anywhere state that it was DNA damage that is the only cause of aging , i said that "entropy damage " . I mean all the damage or problems a living organism can get can and should be attributed to Entropy. I should especificate that i don't mean entropy to be an "entity" , everything in this world tends to go over to disorder , therefor its everywhere.
i agree with you , i formulated my statement about imortality badly, it`s as you say not worth talking about. I just wanted to state that if we find a way to help a living organism to conter entropy more efficient it will at the very least aid prolonging its life cycle

 

[Ryan_m_b]

Castro please post with proper grammar i.e. capitalisation.

dead is the entropy equilibrium , the point of maximum entropy .

An organism is "dead" when it no longer is able to fufill the criteria used to determine if something is alive i.e. it does not respire, there is no brain activity etc.

this can only be reached when the organism is no longer able to "clean " itself .

No it occurs when an organism is damaged/has accumulated enough damage to the extent it can no longer sustain it's life.

I did not anywhere state that it was DNA damage that is the only cause of aging , i said that "entropy damage " . I mean all the damage or problems a living organism can get can and should be attributed to Entropy.

Only in the sense that all chemistry can be attributred to entropy.

 

[castro94]

Well , all the functions of life are basically just for contering entropy. therefore we die when we no longer can conter entropy . when the life function no longer work properly it`s then that the entropy "takes " over and the entropy equilibrium is reached

weell , damage to the body can also be called entropy. if the regular process or part of the body is in "order " than damage to it in any kind wil be equal to disorder , and disorder is entropy .

well i don't agree here either , its not only the chemistry that is affected by entropy , everything is affected by entropy

 

[Pythagorean]

Be careful on a bio/chem forum when using the word entropy to clarify that you are talking about information entropy.

 

[mishrashubham]

Be careful on a bio/chem forum when using the word entropy to clarify that you are talking about information entropy.

He is probably referring to Schrodinger's Paradox (which is not a real paradox btw)

 

[castro94]

He is probably referring to Schrodinger's Paradox (which is not a real paradox btw)

my statement is ended based on schröndinger`s work

 

[Pythagorean]

still, order and disorder is not a robust definition of thermodynamic entropy, which follows from the Clausius Inequality. When you start bringing up order/disorder, your bordering on an information theory discussion.

I've never read Schrodinger's book and that wiki doesn't cite anything, so I have no idea whether Schrodinger formalized his claim in thermodynamics, but it doesn't sound like it to me. Sounds kind of hand wavy.

Another interesting study along the lines is Maxwell's Demon, where some may even argue we have a connection between information entropy and thermodynamic entropy.

 

[phylotree]

still, order and disorder is not a robust definition of thermodynamic entropy, which follows from the Clausius Inequality. When you start bringing up order/disorder, your bordering on an information theory discussion.

I've never read Schrodinger's book and that wiki doesn't cite anything, so I have no idea whether Schrodinger formalized his claim in thermodynamics, but it doesn't sound like it to me. Sounds kind of hand wavy.

Another interesting study along the lines is Maxwell's Demon, where some may even argue we have a connection between information entropy and thermodynamic entropy.

You are stricter than I thought. The entropy in information theory can certainly be used to measure the order or disorder of biological systems, it just can't be used to detail its origin (if we agree to take the genetic changes as the source of information and the outcome of a new species as the informational destination).