Re: Genetic Effects?

["Bjorn Cedervall" <bcradsafers@HOTMAIL.COM>]

>The Sep. 2004 issue of Science & Technology Review from LLNL includes a 

>primer on radiation in a sidebar on p. 6.  In it, the following statement 

>is made: "Exposure to large amounts of ionizing radiation (on the order of 

>hundreds of times the natural exposure levels) increases the risk of. . . 

>genetic mutations that can be passed on to future generations."

>

>Is there any evidence of this (genetic effects) in humans?



-----

Of course they can be passed on to future generations - in theory.

However, it is questionable whether this can be an important problem since 

there is strong selection against any damage on a DNA-level that is severe 

(regardless of its cause) at the germ cell stage, and early embryos. 

Therefore, what will be missed by these natural selection processes will 

reasonably be:



1/ Mutations which play no or small roles during embryogenesis / fetal 

development.

2/ Mutations which will have minor effects on the fitness of the individual 

(each one of us may carry many such mutations).



Among the most important factors that damage our genome on a population 

level (all members of the species defined as the common gene pool) is modern 

medicine. This is ethically an impossible situation because we all want our 

loved ones to survive but nature is brutal and has created a conflict 

between the interest of the individual (and its closest relatives) and that 

of the population (if the population could have "an interest" - here just 

meant to refer to future overall survival). For sexually reproducing species 

(with two sexes) an average of 2 (long term) offspring should survive. We 

set that number 2 aside (population growth) and along with that probably 

increased vulnerability in the future.



I have collected some evolutionary biology links here:

http://www.geocities.com/bjorn_cedervall/Science/evolution_links.html

(I came across tons of anti-evolution sites while going through this stuff

- tons of scary misinterpretations: One of the worst is that selection is 

against

something rather than for (because selection cannot have a positive 

purpose)).



Suggested start:

The high spontaneous mutation rate: Is it a health risk?, PNAS, Vol. 94, 

1997:8380-8386.



For species with more than two sexes the math must be extremely complex - 

Paramecia have 34 different sexes (one opposite sex may be complicated 

enough - even without math :-).



I have simplified some reasoning above but believe that the essence is OK. 

Please add, subtract or modify whatever may be necessary. For more about 

"species" I refer to Ernst Mayr, Stebbins and Dobzhansky as first basic 

stuff - there is a lot of other quality reading out there (Crow and Kimura 

for instance).



My personal action and ideas only,



Bjorn Cedervall      bcradsafers@hotmail.com

http://www.geocities.com/bjorn_cedervall/





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