<< There is such a strong connection between UV 
and nucleotides, that I can't help but think that
UV was instrumental in the origin of life.

(this based on info from Intro to Research in
UV Photobiology, John Jagger) >>


Here is some more on UV from the Jagger book.

7.  "The doses required (in the killing of small cells) in the near -  UV
region are of the order of 1000
times those needed with far UV,"
That suggests that if prebiotic life can protect itself 
from this UV danger region  it should be safe from UV.
8. Because there are repair systems to UV, there must have been severe UV
damage at one time - that forced this selection pressure. "Development of such
mechanisms for maintaining the integrity of DNa over long periods of time may
well have been a crucial prerequisite for biological evolution."
9. The first cells may have had the benefit of providing some protection from
UV. "These cells are generally so big that penetration of far UV becomes a
major problem."
10 A heat source that keeps a planet in the liquid water zone, may not be
enough. "The only part of the solar spectrum at or near the earth's surface (at
the origin) sufficiently energetic to cause simple chemical syntheses is the
ultraviolet region."

And finally this quote.
"The fact that our atmosphere transmits right down to the point (~3000A) where
solar radiation becomes destructive of organic life (and therefore
energetically capable of producing it) is apparently no accident. It lends
strong support to the notion that ultraviolet radiation was an essential factor
in the emergence of life on this planet. In the absence of other information,
we suppose this also applies to the origin of life elsewhere in the universe."

I agree.
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