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Tom Hendricks
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 Posted: Mon Jul 07, 2008 5:50 am Post subject: Coincidence or Clue |
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The major component of life is the nucleotides,
purines (A,G) and pyrimidines(C,T,U). Both strongly
absorb UV light. When life began the earth was
bombarded with unfiltered UV light from the sun.
Why would nucleotides have anything to do with the
origin of life IF they were so strongly absorbent of
the damaging UV lights? Wouldn>t these purines and
pyrimidines be the last thing to be selected for life?
If UV was a danger to the origin of life, surely the
last choice for life chemistry would be chemistry that
absorbed damaging UV.
We have two choices. Either nucleotide absorption of
UV helped start life, or in one of the strangest
flukes, and weirdest case of irony ever, life started
in spite of using chemicals that absorbed the damaging
UV.
Surely the odds favor the former suggestion, and the
absorption properties of nucleotides was somehow a
clue to how life began.
Clearly it>s not a fact, but I think it>s a key clue.
IF this then department: If UV is most damaging on
pyrimidine dimers, then that would suggest purines
played a more important part in the origin. And it
seems to be so. Our energy currency should come from
the purines, ATP and occasionally GTP.
BUT this also says that life was reacting to UV or
there would have been no selection for the purines
over the pyrimidines. (IF UV was the cause of the
chemical selection
Comments?
Tom Hendricks
http://www.daviddarling.info/encyclopedia/U/UV_origin_of_life.html |
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J.A.Legris
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| Posted: Tue Jul 08, 2008 6:19 pm Post subject: Re: Coincidence or Clue |
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On Jul 7, 1:50 am, Tom Hendricks <tom-hendri...@att.net> wrote:
[quote]The major component of life is the nucleotides,
purines (A,G) and pyrimidines(C,T,U). Both strongly
absorb UV light. When life began the earth was
bombarded with unfiltered UV light from the sun.
Why would nucleotides have anything to do with the
origin of life IF they were so strongly absorbent of
the damaging UV lights? Wouldn>t these purines and
pyrimidines be the last thing to be selected for life?
If UV was a danger to the origin of life, surely the
last choice for life chemistry would be chemistry that
absorbed damaging UV.
We have two choices. Either nucleotide absorption of
UV helped start life, or in one of the strangest
flukes, and weirdest case of irony ever, life started
in spite of using chemicals that absorbed the damaging
UV.
Surely the odds favor the former suggestion, and the
absorption properties of nucleotides was somehow a
clue to how life began.
Clearly it>s not a fact, but I think it>s a key clue.
IF this then department: If UV is most damaging on
pyrimidine dimers, then that would suggest purines
played a more important part in the origin. And it
seems to be so. Our energy currency should come from
the purines, ATP and occasionally GTP.
BUT this also says that life was reacting to UV or
there would have been no selection for the purines
over the pyrimidines. (IF UV was the cause of the
chemical selection
Comments?
Tom Hendrickshttp://www.daviddarling.info/encyclopedia/U/UV_origin_of_life.html
[/quote]
Not much UV under the sea or underground. |
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Tom Hendricks
Guest
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| Posted: Thu Jul 10, 2008 7:50 pm Post subject: Re: Coincidence or Clue |
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On Jul 8, 1:19 pm, "J.A.Legris" <jaleg...@sympatico.ca> wrote:
[quote]On Jul 7, 1:50 am, Tom Hendricks <tom-hendri...@att.net> wrote:
The major component of life is the nucleotides,
purines (A,G) and pyrimidines(C,T,U). Both strongly
absorb UV light. When life began the earth was
bombarded with unfiltered UV light from the sun.
Why would nucleotides have anything to do with the
origin of life IF they were so strongly absorbent of
the damaging UV lights? Wouldn>t these purines and
pyrimidines be the last thing to be selected for life?
If UV was a danger to the origin of life, surely the
last choice for life chemistry would be chemistry that
absorbed damaging UV.
We have two choices. Either nucleotide absorption of
UV helped start life, or in one of the strangest
flukes, and weirdest case of irony ever, life started
in spite of using chemicals that absorbed the damaging
UV.
Surely the odds favor the former suggestion, and the
absorption properties of nucleotides was somehow a
clue to how life began.
Clearly it>s not a fact, but I think it>s a key clue.
IF this then department: If UV is most damaging on
pyrimidine dimers, then that would suggest purines
played a more important part in the origin. And it
seems to be so. Our energy currency should come from
the purines, ATP and occasionally GTP.
BUT this also says that life was reacting to UV or
there would have been no selection for the purines
over the pyrimidines. (IF UV was the cause of the
chemical selection
Comments?
Tom Hendrickshttp://www.daviddarling.info/encyclopedia/U/UV_origin_of_life.html
Not much UV under the sea or underground.
[/quote]
Exactly. So that rules out those two for me.
Thermal vents sterilize the sea they don>t start life IMO. Also you
need a dry cycle.
All wet alone is almost impossible chemistry to start life.
Underground would not have any stable and cyclical energy source like
the day/night heat cycle of the sun.
If life began outside of UV, say under the sea, then it is
conceivable that we could
find life with no UV repair genes right? Has any organism ever been
found without UV repair systems?
Does any thermal vent organism NOT have UV protection processes in
their genes? |
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