Re: The role of radioactivity in evolution

Alan Meyer wrote:

I speculate that radiation has played a very minor role in
comparison to other causes of mutations. The reason for this
speculation is that the process of DNA replication is inherently
error prone. Modern eukaryotic cells, such as in humans, are
said to have replication error rates after all proof reading and
correction of about 10^-9. That amounts to an average of 6
errors in a full double set of human chromosomes on each
replication. Prokaryotes have much higher error rates, and early
organisms must have much higher error rates still.

I therefore speculate that natural replication errors greatly
outnumber radiation induced errors in the history of mutations to
DNA.

I could, of course be very wrong. There have probably been
periods in the history of the earth where radiation was much
greater than today.

Albinos get skin cancer because of mutations caused by radiation.

http://www.plasticsurgery-africa.org/albinos.htm

According to: http://calorierestriction.org/pmid/?n=2766562

.....23.4% of albinos in Johannesburg have skin cancer.

Somatic cell mutations are the cause - but cancer can still
affect the course of evolution via selection.

I don't know how radiation-induced mutations compare with
mutations induced by cellular ROS and other garbage - but
my guess would be that - in the absence of radiation defenses -
they could well be fairly significant.
--
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