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Old 12-20-2008, 11:41 AM
 
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This is a cool story to ponder and that is Evolutionary Geneticists at several universities in France have published the Tree of Life showing that all organisms on earth be it humans, animals, plant, bacteria etc. evolved from the ''Mother Organism'' known as ''LUCA'' some 3 billion years ago. Interesting that ancient life was composed of RNA and not DNA as it is now.

More to the story on the link if interested.

Earth's Original Ancestor Was 'LUCA' - Science Daily
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Old 12-20-2008, 12:59 PM
 
Location: Maryland's 6th District.
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Biologists (depending on discipline) are beginning to believe that RNA actually runs the show.

What is even more interesting is that there are some viruses that only consist of single stranded RNA. There was a point in time not too long ago when such a thing would have been considered impossible.
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Old 12-20-2008, 05:25 PM
 
Location: Norfolk, VA
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Its been a while now that people have suggested RNA came first. And before that proteins. Before that, possibly simple amino acid chains and lipids.

As organisms become more complex, more steps get into the process. DNA is pretty much a storage medium, alone it can not do very much. It has to be trancripted and translated into proteins. We know of organisms that consist of only RNA, but none that I know of that has only DNA.

So based on that and other evidence its reasonable to think that RNA came first.
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Old 12-20-2008, 06:37 PM
 
Location: Texas
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I think proteins can be found in space.
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Old 12-21-2008, 01:45 AM
 
Location: Maryland's 6th District.
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Quote:
Originally Posted by rcarrillo View Post
Its been a while now that people have suggested RNA came first. And before that proteins. Before that, possibly simple amino acid chains and lipids.

As organisms become more complex, more steps get into the process. DNA is pretty much a storage medium, alone it can not do very much. It has to be trancripted and translated into proteins. We know of organisms that consist of only RNA, but none that I know of that has only DNA.

So based on that and other evidence its reasonable to think that RNA came first.
To my knowledge viruses are the only things that can have either DNA or RNA, but never both. DNA is transcribed into mRNA then mRNA is translated into proteins or other amino chains.
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Old 12-21-2008, 01:21 PM
 
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What i don't understand is that if everything at one time was RNA as it could self replicate then why did evolution create DNA?
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Old 12-21-2008, 03:00 PM
 
Location: Maryland's 6th District.
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Quote:
Originally Posted by 6 FOOT 3 View Post
What i don't understand is that if everything at one time was RNA as it could self replicate then why did evolution create DNA?
No one knows, but as rcarillo suggested at some point in time RNA figured out that it would be advantageous to create a housing for its library of genetic information. ViralMD might have a better answer. Where ya at?
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Old 12-22-2008, 09:58 PM
 
Location: Norfolk, VA
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Originally Posted by K-Luv View Post
To my knowledge viruses are the only things that can have either DNA or RNA, but never both. DNA is transcribed into mRNA then mRNA is translated into proteins or other amino chains.
Yep. But even DNA only viruses "hijack" a cell's machinery to make mRNA and then proteins. As well as replicate its DNA to make new copies. I don't think there is any organism that can reproduce or survive without using RNA.

Viruses that use only RNA/proteins and never have DNA do exist, again making it seem that RNA is the original item and DNA the derived form.


Quote:
Originally Posted by 6 FOOT 3 View Post
What i don't understand is that if everything at one time was RNA as it could self replicate then why did evolution create DNA?
Quote:
Originally Posted by K-Luv View Post
No one knows, but as rcarillo suggested at some point in time RNA figured out that it would be advantageous to create a housing for its library of genetic information. ViralMD might have a better answer. Where ya at?

There is a nice benefit to keeping your blueprints seperate and secure. There can then be seperation in mechanisms for regulation, repair, and destruction of the two forms. This evidently offers some advantage to the organisms or else it would not have become so common.

It is an elegant system. It allows for mechanisms that preserve DNA and destroy RNA selectively, possibly confering resistance to RNA viruses, destroying RNA molecules over time selectively while not harming DNA and offering one more step in regulation of gene expression. How these things evolved from the soup of nucelotides and amino acid chains into a working cell is an interesting topic.
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Old 12-23-2008, 12:04 AM
 
Location: Texas
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I had read an article a few weeks ago, suggesting that life began from an inorganic substance at the bottom of the ocean. Unfortunately, I've not yet found that article.
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Old 12-23-2008, 08:15 AM
 
13,134 posts, read 40,512,374 times
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Quote:
Originally Posted by rcarrillo View Post
Yep. But even DNA only viruses "hijack" a cell's machinery to make mRNA and then proteins. As well as replicate its DNA to make new copies. I don't think there is any organism that can reproduce or survive without using RNA.

Viruses that use only RNA/proteins and never have DNA do exist, again making it seem that RNA is the original item and DNA the derived form.




There is a nice benefit to keeping your blueprints seperate and secure. There can then be seperation in mechanisms for regulation, repair, and destruction of the two forms. This evidently offers some advantage to the organisms or else it would not have become so common.

It is an elegant system. It allows for mechanisms that preserve DNA and destroy RNA selectively, possibly confering resistance to RNA viruses, destroying RNA molecules over time selectively while not harming DNA and offering one more step in regulation of gene expression. How these things evolved from the soup of nucelotides and amino acid chains into a working cell is an interesting topic.
That's a great post rcarrillo !! As soon as my 24 hr limit is up you have some rep points (4) from me.

6/3
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