Register | Sign In


Understanding through Discussion


EvC Forum active members: 65 (9162 total)
4 online now:
Newest Member: popoi
Post Volume: Total: 915,817 Year: 3,074/9,624 Month: 919/1,588 Week: 102/223 Day: 0/13 Hour: 0/0


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
Author Topic:   Manipulation of DNA by cells?
herebedragons
Member (Idle past 858 days)
Posts: 1517
From: Michigan
Joined: 11-22-2009


(1)
Message 34 of 36 (671103)
08-22-2012 10:33 AM
Reply to: Message 31 by Taq
08-21-2012 5:18 PM


RNA world hypothesis
Origin of life? Very difficult to say. I think only the broadest strokes can be pulled from modern genomes. For example, we can see a central role for RNA in modern life. It acts in many different roles, from gene regulator to producer of proteins to enzyme. I think this is strong evidence that RNA was the primary player in the first life. RNA can act in all of the roles that are necessary for life, from inheritance to enzymatic reactions.
RNA is much less stable than DNA and is prone to hydrolysis. Stable, functional RNA units are usually associated with proteins and involve complex folding patterns as contrasted to DNA structures. Use of RNA as the main storage unit would not be impossible but rather energy intensive, not particularly conducive to early life with lower energy resources (assuming photosynthesis, mitochondria, electron transport and such were not in existence yet)
RNA is not known to self replicate in nature (at least as far as I know) and is instead transcribed from DNA. I know they have created self-replicating RNA in the lab which does suggest that RNA could self-replicate. But in nature, even viruses need a DNA host in order to replicate. RNA also has the base Uracil rather than Thymine which makes it more subject to mispairings than DNA (which could be a good thing or a bad thing for early life).
As far as the role RNA plays in modern organisms ... without DNA regulation of these processes it is only speculation of what RNA's role would be in early life. It shows that RNA can perform these functions and certainly does play a central role in modern life, but it is unclear that RNA could perform these functions without DNA regulation.
I know you are aware of all these things, you are not arguing from ignorance. So I wonder how you consider that there is "strong evidence" that RNA was the primary player in early life? At best I think you could say "conceptually possible".
HBD

Whoever calls me ignorant shares my own opinion. Sorrowfully and tacitly I recognize my ignorance, when I consider how much I lack of what my mind in its craving for knowledge is sighing for. But until the end of the present exile has come and terminated this our imperfection by which "we know in part," I console myself with the consideration that this belongs to our common nature. - Francesco Petrarca

This message is a reply to:
 Message 31 by Taq, posted 08-21-2012 5:18 PM Taq has replied

Replies to this message:
 Message 35 by Taq, posted 08-22-2012 10:56 AM herebedragons has not replied

  
Newer Topic | Older Topic
Jump to:


Copyright 2001-2023 by EvC Forum, All Rights Reserved

™ Version 4.2
Innovative software from Qwixotic © 2024