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Author Topic:   Early DNA replication systems
Loudmouth
Inactive Member


Message 3 of 14 (188210)
02-24-2005 5:22 PM
Reply to: Message 1 by jjburklo
02-24-2005 1:37 PM


quote:
I was wondering what the current theories are as to early DNA replication systems. It seems that life could never have been passed on if there was never a precursor to the Polymerases we see today. In fact, would there not have had to be a replication system at the time of the first cell being formed? I've done some research, however, the only thing I can find on polymerases are descriptions of function, and nothing touching on the evolutionary precursors to it.
The answer is that DNA may not have been the first genetic material. RNA can carry both genetic information and carry out chemical reactions. The RNA World Hypothesis states that the first replicators may have been short stretches of RNA that carried out chemical reactions that resulted in self replication. This may have required RNA to build polypeptides, copy itself, or make new and different RNA molecules.
For an overview I would check out this site. And an excerpt from that site:
Today, research in the RNA world is a medium-sized industry. Scientists in this field are able to demonstrate that random sequences of RNA sometimes exhibit useful properties. For example, in 1995, a group of researchers reported "Structurally Complex and Highly Active RNA Ligases Derived from Random RNA Sequences" (4). (Ligases are enzymes that splice together other molecules such as DNA or RNA.) The results are interestingthey suggest that randomness can produce functionality. The authors interpret the results to mean that "the number of distinct complex functional RNA structures is very large indeed."

This message is a reply to:
 Message 1 by jjburklo, posted 02-24-2005 1:37 PM jjburklo has replied

Replies to this message:
 Message 4 by jjburklo, posted 02-25-2005 6:32 PM Loudmouth has replied

  
Loudmouth
Inactive Member


Message 8 of 14 (189185)
02-28-2005 10:56 AM
Reply to: Message 4 by jjburklo
02-25-2005 6:32 PM


quote:
The site did go on to give some other interesting theories as to the origin of information, none which seemed to hold its weight.
All of the information is contained in the oxygens, hydrogens, nitrogens, and phosphorous that makes up RNA. For example, oxygen and hydrogen carry information in their valence electrons. This information allows the reproducible creation of H2O when oxygen and hydrogen are combusted. It is this same type of information that allows reliable and reproducible chemical reactions that resulted in life.

This message is a reply to:
 Message 4 by jjburklo, posted 02-25-2005 6:32 PM jjburklo has not replied

  
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