Re: Fwd: Single and double strand DNA breaks -Reply

[Andrew Karam <karam.1@osu.edu>]

I think that Joelle and Drew have both pretty much hit on what I was
wondering.  Could alpha damage (and DSBs be so damaging and difficult to
repair because high-LET radiation was not a major concern until relatively
late in the history of life?  As Joelle noted, this is uncharted territory
for me, but interesting to speculate about.  I would be very interested in
hearing (on-list of off-list) from anyone who may have more informed
speculation or who may have done (or heard about) research in this area.  

Another corollary comes to mind, too:  Does the degeneracy of the DNA code
(ie multiple code sequences for many amino acids) reflect the environment
in which DNA and its repair evolved?  For example, there are more codons
for arginine (5) than there are for Methionine (1).  Is this just the way
things happened to turn out, or is methionine (or the bases that code for
it) more resistant to mutation than arginine?  Or could methionine have
evolved at a different time in the history of life when mutations were less
likely to occur?

Just some more Friday afternoon musings, but I am very interested in what
anyone "out there" might think.

Have a good weekend.

Andy

The opinions expressed above are well-reasoned and insightful.  Needless to
say, they are not those of my employer. (with apologies to Michael Feldman)		

Andrew Karam, MS, CHP					(614) 292-1284 (phone)
The Ohio State University 					(614) 292-7002 (fax)
Office of Radiation Safety					"The mind is not a vessel to
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(karam.1@osu.edu)