Re: junk DNA or buffer DNA
Geoff Smith (geoffs@unixg.ubc.ca)
Wed, 18 Mar 1998 13:22:39 -0800
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> From: John K Clark <johnkc@well.com>
> To: extropians@extropy.com
> Subject: junk DNA or buffer DNA
> Date: Wednesday, March 18, 1998 8:48 AM
>
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> Using DNA to shield things from X rays would be like using tissue paper
as
> protection from an anti tank gun. If you want to decrease the rate of
> mutation then increase the rate of DNA repair, that's what bacteria do.
The
> bacterium Micrococcus radiodurans, like all bacteria, has much less junk
DNA
> than a human or any eukaryotic animal, yet it will thrive even in an
> environment of 6.5 million roentgens of Gamma rays, 10,000 times less
would
> kill a human in minutes.
Just increasing the rate of repair is not enough. These bacteria, and may
others, including some lower eukaryotes, have an enzyme photolyase which
splits UV-induced photodimers. I don't know why the enzyme isn't present
in human skin... someone entrepreneurial out there should put photolyase in
sunscreen.
Geoff.