RE: Radiation Hormesis

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

>Interesting.  What were the doses?



 >

 > We had and interesting laboratory experiment in

 > Radiation Biology when I was in college where we irradiated bean seeds, 

fruit

 > flies, and onion root with low, med, and high doses from a Co-60 source 

from a local hospital.

-----------------



When some Drosophila sp. populations were irradiated (10 Gy per generation 

and mating type (female and male - that is actually a total of 20 Gy to the 

relevant germ cells), each of the first three generations) and compared to 

unirradiated populations and then followed over the next two years, the 

irradiated populations were doing better = the populations were larger 

(published in 1969 if I recall the ref. correctly - about 4-5 pages in 

PNAS). It should be emphasized that this was on some kind of nutritionally 

restricted food and as it was an experiment no alleles (that potentially 

could have been beneficial) could come as inflow from other parts of the 

population. There was a tendency of more individuals dying during the first 

generations of the irradiated populations as compared to the unirradiated 

populations (the experiment was repeated several times with the same 

outcome).



This not about hormesis (a term which in this case may distract the reader 

from the mechanism): This is about natural selection where some individuals 

died (first three generations) from acute effects and where less fit 

individuals got a tougher competition (were statistically selected against) 

from individuals which were better fit (next 50 generations or so).



I am sure that there are Drosophila specialists who could make better 

comments to this.



My personal reflections and ideas only,



Bjorn Cedervall   bcradsafers@hotmail.com



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