[ RadSafe ] uranium solubility and acute and chronic exposures on the Russia-Georgia border
bcradsafers at hotmail.com
Tue Aug 12 06:02:57 CDT 2008
> You wrote, "If you are trying to imply that a mutation burden could> lead to some NEGATIVE genetic changes on a population level it just
> tells that you haven't studied any of the key messages from the evolution> biologists and what they developed over the last 80 years."
> That is false. When does a mutation burden not result in genetic> changes? Certainly the evolution biologists should get more attention> than the creationist biologists, who tend to say silly things that,> for example, imply that evil has parents, or roots, and is not often> the result of the spontaneous chance events such as nuclear decay.
I have added the word NEGATIVE to my previous comment (see above). The reason for my statement is that deleterious/less fit mutations statistically are subject to a stronger selection pressure. Such mutations arise all the time (and much more frequently than beneficial mutations) as they are caused by phenomena such as endogenous metabolism, natural radiation and other factors. Individuals carrying too many of such mutations (actually alleles) will not survive to reproductive age and with their death several "bad alleles" then disappear with each such death. What is good or bad genetically, however, is dependent on the outer environment as well as all other alleles in each individuals - it is the combined effect of these alleles that will determine whether the individual (phenotype) is a target that will be selected against before the individual has a chance to produce offspring. Gene pools (populations) can undergo dramatic changes over just one or two generations.
As a clarification: All this referring to population genetics is about sexually reproducing populations.
It is only with very small populations that a very high extra mutational load the first 1-2 generations possibly could lead to anything but radiation could probably not do anything like that - the exposure needed to would have to be in a magnitude close to that which could lead to tissue ("non-stochastic") effects. That rules out DU exposure as being relevant - it would be far too low.
Here is a reference that provides some perspective to the issue:
Creationists stick to typological thinking (that each species is "typical" or of a "type") which is contradictory to population genetics: It is the variation (all genetically unique individuals) which results in the capacity of populations to cope with changes in the environment and mutation pressure. Add to that genetic truncation (as discussed above for single individuals carrying several "bad" alleles) and crossing over - the bottom line becomes a capacity to transiently "buffer" genetic loads of the gene pool. Much of this can be understood quite clearly if you read a couple of Ernst Mayr´s (1904-2005) books published after say 1960 (he published at least 65 books (+many scientific papers) from 1927-2004 - the last one is an excellent start).
My personal ideas only,
Bjorn Cedervall bcradsafers at hotmail.com
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