Re: Evolving radiation resistance

["jjcohen" <jjcohen@PRODIGY.NET>]

And to complicate matters further, if there were some objective scientific

method of measuring the radiation resistance/sensitivity of individuals, it

is reasonable to assume that for population groups, there would be a wide

range even within specific localities and ethnic groups, as is the case with

almost all other harmful agents. Setting reasonably safe exposure limits in

such a situation could be somewhat tenuous. So the tacit, and incorrect ,

assumption has been  that humans are homogeneous in this regard. Should the

radiation protection community ever decide to deal with questions of

variable radiation sensitivity who should they protect----- the average

individual, the most sensitive individual, or what?

Jerry Cohen



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

From: A Karam <paksbi@rit.edu>

To: <radsafe@list.vanderbilt.edu>

Sent: Thursday, September 02, 2004 11:15 AM

Subject: Evolving radiation resistance





> One thing to remember about evolution is that it only works if organisms

> die before they can reproduce.  Natural background radiation levels,

> even in Kerala or Ramsar, are not likely to cause death from cancer when

> a person is in their teens or 20s.

>

> We should also remember that natural background radiation is responsible

> for only a few percent of spontaneous DNA damage.  This means, again,

> that even a dramatic increase in background radiation levels will not

> contribute markedly to additional DNA damage and is therefore unlikely

> to cause a marked increase in carcinogenesis.

>

> Accordingly, it seems unlikely that living in these areas would

> contribute any selection pressure towards developing a resistance to

> radiation at these levels.

>

> Sorry....

>

> Andy

>

> P. Andrew Karam, Ph.D., CHP

> Research Assistant Professor

> Rochester Institute of Technology

> Department of Biological Sciences

> 85 Lomb Memorial Drive

> Rochester, NY  14623

> +1 585-475-6432

> karam@mail.rit.edu

>

> "If A is success in life, then A equals X plus Y plus Z. Work is X; Y is

> play; and Z is keeping your mouth shut." - Albert Einstein

>

>

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

>

> One factor that I have not seen discussed in the hormesis debate is

> natural

> selection. Since man has for ever been exposed to natural radiation, is

> it

> not reasonable to assume that natural selection has reinforced our

> resistance to any deleterious effects? Is it possible that the native

> population of Kerala, for instance, has a greater resistance to

> radiation

> than areas with low natural radiation?

>

> My personal (uneducated!) feeling is that reasonable levels of natural

> radiation (and occupational exposures to similar types and energies of

> radiation) is something the human organism (and all other terrestrial

> organisms) has adapted to. And that, as Dale states, the confounding

> factors are so numerous (and over-riding) that confirmation, or

> otherwise,

> is extremely difficult.

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