RE: Radiation Hormesis -- or not

["Flanigan, Floyd" <Floyd.Flanigan@nmcco.com>]

In my view, it is not whether the favor falls with positive or negative mutation, rather the likelihood of the survival of the subject cell, plant or organism. If the mutation is an improvement, the subject would tend to thrive and reproduce, possibly passing on the trait to one or more of its offspring. This improves the subject down-line and would theoretically make it stronger and more likely to survive than any non-mutated subjects of the preceeding down-line.



Floyd W. Flanigan B.S.Nuc.H.P.



-----Original Message-----

From: John Jacobus [mailto:crispy_bird@YAHOO.COM]

Sent: Tuesday, January 27, 2004 7:37 AM

To: Neil, David M; Carl Speer; radsafe@list.vanderbilt.edu

Subject: RE: Radiation Hormesis -- or not





That is my point.  ". . . a mutational effect, which 

changes random genes, would produce random phenotypes.

 ." While they are not uniformly superior neither are

they uniformly inferior.  



I am not a expert in plant genetics, so may be the

irradiation of seeds is a hormetic effect.  I raised

the question since it is frequently cited, and I have

not seen any detailed study of genetic changes, which

to me are not hormetic.  I think someone else said

that chemicals can also cause drastic changes in plant

responses.  This is all well and good, but what is the

implications to humans?



--- "Neil, David M" <neildm@id.doe.gov> wrote:

> Why would a genetic mutation favor a negative

> effect?  Because there are lots more ways to "do it

> wrong" than there are to "do it different but

> right".  Change as little as one peptide in insulin,

> for example, and you don't survive to breed without

> medical support.

> 

> To use your example, proto-primates which could grip

> better (within natural variation) could climb

> better, and therefore  could escape danger easier

> and survive to breed, and also had easier access to

> food (either pick-a-fruit or grab-a-bug) and

> therefore bred more frequently, more successfully

> and longer.  

> 

> As stated, the uniformity of the effect indicates

> the nature of the effect: a mutational effect, which

> changes random genes, would produce random

> phenotypes, not uniformly superior phenotypes.

> 

> Dave Neil  

> B.A. Zoology, University of South Florida

> 

> 

> -----Original Message-----

> From: John Jacobus [mailto:crispy_bird@yahoo.com]

> Sent: Monday, January 26, 2004 2:17 PM

> To: Neil, David M; Carl Speer;

> radsafe@list.vanderbilt.edu

> Subject: RE: Radiation Hormesis -- or not

> 

> 

> Why would a genetic mutation favor a negative

> effect? 

> After all, evolution shows that genetic effects are

> positive since they allow the organism to adapt. 

> Primates did not get opposed thumbs by willing it to

> happen.  It was genetics.

> 

> Again, my statement was that it should have been

> checked to see if it was a genetic mutation by

> following the growth pattern of the off-spring. 

> 

> <SNIP>





=====

+++++++++++++++++++

"I have sworn upon the altar of God, eternal hostility against every form of tyranny over the mind of man."

Thomas Jefferson



-- John

John Jacobus, MS

Certified Health Physicist

e-mail:  crispy_bird@yahoo.com



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