Here's some support for my idea that UV may have been a key
in prebiotic chemical selection - and it may have helped in
RNA polymerization
newscientist.comnews.jspOpen ↗
Excerpt:
The World's No.1 Science & Technology News Service UV light
may have sparked life on Earth
18:18 28 May 03 NewScientist.com news service Ultra-
violet light, long thought to be an impediment to the
early formation of long organic molecules, may in fact
hold the key to the origin of life, according to a new
study. Intense UV rays from a young Sun bombarded the
early Earth and were thought likely to destroy any
exposed organic molecules. But a new mathematical model
implies the radiation actually helped select out the
molecular seeds of life.
(snipped)
Peculiar properties
Life on Earth is thought to have evolved about 3.7 billion
years ago, when there was no protective ozone layer encasing
the planet and UV radiation was 100 times more intense than
today. The nucleotides that make up RNA have three
components - a sugar, a phosphate and nitrogen-containing
base. "And these bases have very peculiar properties of
being extremely efficient at quenching UV light," says
Mulkidjanian, protecting the sugar and phosphate components
which form the spine of the chain. The team fed data on the
photochemistry of various organic molecules into a computer
model designed to simulate the effects of UV light on
stability. "The effect was very pronounced in RNA," he says.
In the presence of strong UV light, RNA was much more likely
to form long chains than other molecules.
Also there is this old idea: the high point of absorbency on
the spectrum is 260 nm - and IF that is a key to life and IF
there is other life out there - then perhaps they will be
signaling to us at the universal 260nm -
A and U = 260nm, C = 275 nm, G 255 nm. Note that with these
differences there may have been chemical prebiotic selection
between the WC pairs.
Tom