Thread: DNA creation

where did DNA come into play in the development of the first living thing? did DNA come first and code for the proteins to create the first living thing, or did the first living thing randomly come into being and then DNA was made that coded for its particular proteins (and ultimately physical form)? If the latter, how was the DNA created, what coded for IT? And also, if DNA came first, how would a living organism arise from that? How did the DNA cause the creation of proteins, when there would be no mechanisms to assemble these proteins (or at least there would be none that I'm aware of)? I know I asked a lot of questions in there, so any answers to any parts would be appreciated. Thanks

Short answer: Neither.

You want to look to RNA for the types of answers you are after.

From here: http://biology.plosjournals.org/perl...l.pbio.0030396

In the beginning, according to the so-called genes-first camp, was a single RNA molecule, both code and catalyst. Such a “replicase” would have catalyzed its own replication, and also provided the template on which the copy was made.

The whole article is not too long and thoroughly interesting.

Also, the process isn't random.

See here: http://www.talkorigins.org/faqs/faq-misconceptions.html with the sub heading: "The theory of evolution says that life originated, and evolution proceeds, by random chance."

The answer to your question is an RNA with reverse transcriptase activity.
No one has ever found any direct evidence for the existence for these. But people are not done looking yet!

Sorry for a reply this late... but this is something interesting... according to PatrickForterre's investigation ( News Feature: Nature, Vol 439, Jan 12, 2006, page 130 --- Full Article: Biochimie, vol 87, 2005, pags 793 - 803) found another hypothesis... that DNA was created by viruses during the RNA World, in order to surpass the RNA defenses of the cells back then... and since DNA was a more stable molecula than RNA, cells finally incorporated it into them. Love that theory... :P

Originally Posted by Cantero

Sorry for a reply this late... but this is something interesting... according to PatrickForterre's investigation ( News Feature: Nature, Vol 439, Jan 12, 2006, page 130 --- Full Article: Biochimie, vol 87, 2005, pags 793 - 803) found another hypothesis... that DNA was created by viruses during the RNA World, in order to surpass the RNA defenses of the cells back then... and since DNA was a more stable molecula than RNA, cells finally incorporated it into them. Love that theory... :P

Yes, so do I. RNA-world viruses must have developed early on as parasitic and symbiotic opportunists. Sex developed early on, too, and I favor the theory that sex became necessary to allow genes a way to excape their parasites.

The RNA-world view seems credible enough to me, especially now that scientists have found ways to make synthetic RNA. What I still don't know, however, is whether or not those nucleotides of synthetic RNA had abiogenic origins. If their origins were biogentic then that doesn't help to explain the natural origins of the first nucleotides.

—Crabby

The answer to your question is an RNA with reverse transcriptase activity.

Uhhh.
No.
Reverse transriptase is an overly complicated mechanism for the earliest RNA lifeforms. In fact, reverse transcriptase is only found in an exceedingly small line of viruses called retroviruses...
How you would connect this to the beginnings of life is beyond me....


Anyway.
The debate rages on which came first.
Metabolic activity or transcription.
Did they arise together? Or did they arise separately and integrated into a single organism at some later date?

A key concept to look for is the ribozyme.