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The existence of RNA and DNA: What allowed genetic material to exist?


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This is the thread where I complain about genetic and cellular evolution.

 

One of my pet peeves with evolution is the existence of DNA and RNA. In what I've studied about evolution, what bothers me is that somehow, magically DNA, RNA, or some pre-cursor to those molecules found a way to exist on planet Earth. The reason this bothers me is because I cannot fathom conditions that would allow and enable RNA or DNA to maintain itself for long periods of time without denaturing. If the molcules were made in the ocean, I don't understand what the molecules would not have denatured over time and been destroyed. The other issue that bothers me is how exactly these molecules found themselves into a fatty-layered membrane in order to replicate. I cannot conceive of a way for such to occur; and at best, I've read that maybe some kind of catalyst caused the membrane to occur (I lost the source long ago); but that doesn't mean that RNA, DNA, or some genetic precursor should have been able to get into the membrane. And even if it could, how is it going to prevent itself from denaturing?

 

Why didn't genetic material get destroyed early in its evolution? What allowed it to maintain itself?

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First off...

 

...what bothers me is that somehow, magically DNA, RNA, or some pre-cursor to those molecules found a way to exist on planet Earth.

Emphasis added. It wasn't magic, it was chemistry. RNA and DNA are just organic molecules, and organic molecules obey the laws of chemistry in their formation.

 

And your entire argument is basically an argument from incredulity. Just because you can't imagine how it could happen, doesn't mean it did not (or cannot) happen. I can't imagine how tiny particles of oxidation on spinning disks can store petabytes of information, but they do.

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In addition, what do you think affects DNA and RNA the most (hint: people that are skilled in isolating RNA also usually have very stable samples, why is that)? Also keep in mind that early nucleic acids do not necessarily have the same structure as the one we have today (read up on PNA, for example).

DNA on the other hand is super-stable which is one of the reasons why there was a group that support the DNA first hypothesis.

 

Furthermore, how long do you think does the half-life have to be? Remember cell cycle times do not apply in this situation. The critical rates are the synthesis vs degradation rates.

The general assumption is that membranes came much later with peptides and nucleic acids being the early replicating molecules. Lipids are likely a later addition.

 

I agree with Greg, since it is an argument from incredulity, I wonder why it should become a pet peeve. There is quite a body of literature out that one could check out if one really wanted to learn about this topic. While there is no definite answer, it does illuminate the biochemical issues to a certain extent.

Edited by CharonY
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