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Attitudes to life extension via genetic engineering

Patrick O'Neil patrick at corona
Wed Feb 15 21:06:06 EST 1995

On Wed, 15 Feb 1995, Eugen Leitl wrote:

> 1> Increasing expression of superoxide-dismutase and other anti-oxidation
> 1> enzymes; this will make the body more resistant to free radicals,
> 1> environmental dangers and perhaps slow aging somewhat.
> Probably true. Difficult to estimate additional life span in years.

There is a present balance in its production verses a biological need for 
free radicals.  If you simply increase expression of free radical 
quenchers such as SOD, you are insured to dork up biologically important 
radical reactions in regards to nucleic acid synthesis, electron 
transport, immune response, and a host of others known and unknown.  The 
body's balance of expression vs inhibition of various enzymes is set for 
best performance under the circumstances.  I am not saying that any 
increase in expression is sure to screw up the works, but on the other 
hand, it is not just as simple as saying, "Ah, free radical scavenger.  
Just increase the expression of that gene and viola!  Happy, healthy 
body!"  There are many other things involved that would have to be 
considered.  None of the enzymatic systems within our bodies are 
completely independent of other reactions.
> 1> Increase of DNA correction rate by increasing expression of repair enzymes
> 1> These two methods don't appear that hard to use, since we only need to
> 1> create more copies or promoters for the genes (evolution haven't done 
> 1this,
> 1> since it would require more energy (which we humans have plenty of) and
> 1> long lifespan is normally not selected for).
> Very true and sound arguments.

But...All the repair enzymes in the world will not stop mutation.  You 
may decrease mutation rate somewhat but there are mutations that can get 
past all the editing machinery.  Reducing mutation rate, in any case, 
would only help to reduce the occurrence of cancer, not affect lifespan 
outside of cancer.
  On another note, natural selection favors a certain minimal level of 
mutation in order that diversity is evolved, thus allowing for adaption 
to exist in the first place.


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