DNA & Aging

Steve Chambers steve at chambers.ak.planet.co.nz
Mon Nov 6 18:41:44 EST 1995


In <Pine.SOL.3.91.951106030413.3340G-100000 at minerva> "Paul Boduch (ES 1997)" <pboduch at minerva.cis.yale.edu> writes:
>	I've recently come across a really interesting article on food 
>mutagens & DNA. It now seems quite clear that a lot of cancer is not only 
>genetic, but also the result of some pesky molecules screwing up our code.
>I was wondering if aging could be an aggregate result of years of damage 
>to DNA & errors too numerous to be corrected in a timely fashion.
>Aging definitely has to be either genetic or environmental like cancer. 

Why not both?

>If the latter is the case, then couldn't it be simply fixed by:

>	1) freezing a bunch of our youthful undamaged DNA
>	2) and then breeding in large quantity 
>	   a hybrid virus containing its own injection 
>	   mechanism & our DNA
>	3) and then simply infecting ourselves with this potion
>           of youth

Probably the first to explore this line of reasoning were Failla and 
Szilard (independently it seems).  And Orgel's Error Catastrophe theory
is an interesting development on the theme.  Although there's no doubt 
that somatic mutations are a factor in aging organisms, there's no way
that we could attribute all aging phenomena to such damage.

Aside from the obvious (that people and organisms die from a host of
conditions that don't seem to depend on genetic damage), there are a 
few observations worth mentioning: 

 In wasps, for example, the haploid (only one set of genes) male lives
 just as long as the diploid (two sets - ie a spare set) female.

 Low level radiation (which damages DNA) can _increase_ the lifespan of 
 some animals.

 Survivors of the Atomic blasts at Nagasaki and Hiroshima were exposed
 to enormous levels of DNA damaging radiation.  Yet they were found to 
 "age" at the same rate as other matched-sample Japanese.

I won't even attempt to address 2) of your solution.  It makes today's
gene therapy problems look like a stroll in the park.  But who knows,
it may be possible in the not-too-distant future to create a viral
vector that can "correct" some common mutations - perhaps those that
seem to "power down" our mitochondria with age.

>If the former is the case, then we could simply cure this terminal 
>disease by finding the portion of our code responsible for it and 
>eliminate it.

The "portion" you speak of could turn out to be nearly all of our
coding DNA (and some structural stuff besides).  Evolutionary theory
suggests that we should treat with suspicion _every_ biological process 
that makes us what we are.  Eliminating gene-influenced processes that 
contribute to aging is not an option.

Steve

-- 
 ________________________ 
(I_lurk,_therefore_I_am!_\  ,,,                           Steve Chambers
                           (o o)          steve at chambers.ak.planet.co.nz
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