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How did DNA evolve?
Evolution assumes DNA exists, but as yet no account has been provided as to how

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How did DNA evolve?

jeeprs
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Posted 10/06/09 - 02:58 AM: Subject: How did DNA evolve?	#1
Evolution and genetic theory are actually different disciplines, but they are, of course, inextricably intertwined, no more so than in the account of the origins of life. Now there is abundant evidence for the descent of species. Yet the descent of species seems to assume the existence of DNA. So how did DNA evolve? Would this process have been subject to the same processes as the evolution of species, and if so, how? How could proto-DNA seek evolutionary advantage? Is there, or could there be any, evidence for how this came about? Or is it forever to remain in the field of speculative hypotheses?

swstephe
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Posted 10/06/09 - 06:40 AM:	#2
Not speculative at all. Try this dry but well-organized website: http://www.evolutionofdna.com/, for example. DNA and speciation would evolve in parallel. The selection of organisms would define the survival of strands of DNA. DNA can evolve by itself -- just look at viruses and retro-viruses.
Ethics is the measuring of morality. Morality is the measuring of good. Good is the measuring of benefit. Benefit is the measure of values.

jeeprs
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0 of 1 people found this post helpful Posted 10/06/09 - 06:15 PM:	#3
Thanks - interesting site. Still speculative, however, and says that in the first paragraph. It is replete with 'what may have...' statements. But I will read up on it, it looks quite well researched. (Although one type of objection that I recall is that there are hundreds of billions of ways for the so-called 'building block molecules' to combine that are not conducive to the formation of any kind of replicable entity...) Edited by jeeprs on 10/06/09 - 06:23 PM

jsidelko
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Posted 10/06/09 - 06:31 PM:	#4
The emergence of DNA preceeded natural selection. There are trillions upon trillions of different ways DNA could have existed in forms that are not conducive to the evolution of life. I see only two possible solutions: the anthropic principle where our universe is one among many or intelligent design where life forming DNA was deliberately selected.
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jeeprs
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Posted 10/06/09 - 07:25 PM:	#5
Here is an interesting article abstract from a medical journal (note I am much more a platonist than creationist or ID theist) "Before the Darwinian revolution many biologists considered organic forms to be determined by natural law like atoms or crystals and therefore necessary, intrinsic and immutable features of the world order, which will occur throughout the cosmos wherever there is life. The search for the natural determinants of organic form-the celebrated "Laws of Form"-was seen as one of the major tasks of biology. After Darwin, this Platonic conception of form was abandoned and natural selection, not natural law, was increasingly seen to be the main, if not the exclusive, determinant of organic form. However, in the case of one class of very important organic forms-the basic protein folds-advances in protein chemistry since the early 1970s have revealed that they represent a finite set of natural forms, determined by a number of generative constructional rules, like those which govern the formation of atoms or crystals, in which functional adaptations are clearly secondary modifications of primary "givens of physics." The folds are evidently determined by natural law, not natural selection, and are "lawful forms" in the Platonic and pre-Darwinian sense of the word, which are bound to occur everywhere in the universe where the same 20 amino acids are used for their construction. We argue that this is a major discovery which has many important implications regarding the origin of proteins, the origin of life and the fundamental nature of organic form. We speculate that it is unlikely that the folds will prove to be the only case in nature where a set of complex organic forms is determined by natural law, and suggest that natural law may have played a far greater role in the origin and evolution of life than is currently assumed." From http://www.ncbi.nlm.nih.gov/pubmed/12419661 I am warming to the idea that maybe many forms are imprinted into the fabric of reality like templates which then take shape in accordance with the exigencies of particular situations. So it is not as if there is a designer fiddling with the details (an idea I find grotesque) but that the design principles are embedded from the outset. And this seems Platonist.

Kwalish Kid
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Posted 10/06/09 - 07:52 PM:	#6
jsidelko wrote: The emergence of DNA preceeded natural selection. This is unlikely, since there are good reasons to believe that organisms replicating using RNA predated DNA and there were probably organisms with other means of replication before that. Once there were any organisms with replication and heredity, there would have been selective pressures. Having something like RNA or DNA is itself a trait that is beneficial in a great many circumstances.
"Scientific truth is always paradox, if judged by everyday experience, which catches only the delusive nature of things." - KM, V, P and P Can you pass Religion 101?

jeeprs
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0 of 1 people found this post helpful Posted 10/07/09 - 12:54 AM:	#7
Everything written about the 'evolution of DNA' is irrefutably speculative. There is no extant evidence how it occurred and all of the attempts to re-create it are couched in terms of 'it seems likely that...', 'it might have developed as....' and so on. this includes the evolution of DNA site given above. As said, I don't think 'the divine designer', conceived as an actor in the drama, is conceivable. But the idea that the templates for living beings are somehow embedded in the fabric of the cosmos is another thing altogether. This is basically Platonist: the effluegence, the overflowing of the divine intelligence, the Universe as an idea. Sure as hell beats 'chance' in my book. Edited by jeeprs on 10/07/09 - 01:31 AM

Kwalish Kid
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Posted 10/07/09 - 06:22 AM:	#8
"Speculative" does not mean "without evidence". As it is now, there is far more evidence for the fact and nature of the evolution of DNA than for any other explanation. There is also no evidence for some kind of body plans in a platonic sense. Indeed, that is one of the important things that Darwin discovered and established. The discovery of DNA reinforced this claim, and even if DNA was created, it still does not behave in such a way as to suggest platonic forms.
"Scientific truth is always paradox, if judged by everyday experience, which catches only the delusive nature of things." - KM, V, P and P Can you pass Religion 101?

swstephe
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Posted 10/07/09 - 06:54 AM:	#9
Calling something "speculative" sounds like a renewed approach at the old "evolution is just a theory". Sure, all scientific models, especially when talking about past events, is a form of speculation called a "hypothesis", which makes certain predictions about experimentation that could demonstrate how that particular scenario would play out and what evidence should be looked for that would add weight to that particular scenario which can be tested. A hypothesis about the distant past can probably never be firmly proven, (we'll never know, with 100% certainty, who killed JFK, for example). But arguing that a model for evolution of DNA is "speculative" ends up to be a variation on "negative proof" or "argument from the gaps". Nothing can be asserted automatically true simply because something isn't certain. The burden of proof is on the Platonist to come up with hypothesis, model, prediction and tests to assert the validity of that model. How would you go about setting up an environment when the "templates for living beings ... embedded in the fabric of the cosmos" would produce life out of some inorganic environment? So far, I think an evolution of proteins and RNA has a bit more academic support.
Ethics is the measuring of morality. Morality is the measuring of good. Good is the measuring of benefit. Benefit is the measure of values.

Kwalish Kid
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Posted 10/07/09 - 07:28 AM:	#10
Actually, the burden on the Platonist is on getting us to remember the forms that we are already aware of from the time before we are born. I love philosophy jokes.
"Scientific truth is always paradox, if judged by everyday experience, which catches only the delusive nature of things." - KM, V, P and P Can you pass Religion 101?

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