On Tuesday, August 13, 2013 3:17:48 PM UTC-4, Brent wrote:
>  On 8/13/2013 12:00 PM, Chris de Morsella wrote:
> John >> Epigenetic changes do not change the sequence of bases in DNA, and 
> more important I see no evidence that the body has learned any lessons. I 
> see no evidence that epigenetic changes are more likely to happen in the 
> direction of greater adaptability rather than the reverse. All I see is the 
> environment causing random changes in hereditary factors that, like all 
> changes, are more likely to be harmful than helpful.  
> Sure, but then neither do random mutations to an organisms DNA, imply that 
> the body has learned anything either. The introduction of some random 
> change is either harmful, beneficial or of little or no consequence to the 
> individual, whether this phenotypical change is the result of inhibiting or 
> promoting the expression of some underlying DNA or how that DNA get's 
> transcribed, or is the result of an actual change in the individuals 
> sequence of DNA.
> What you say about epigenetic changes: "environment causing random changes 
> in hereditary factors" applies as much to the classical hereditary 
> mechanism of DNA changes. 
> Evolution only happens after multiple generations of selective pressure 
> have either, presumably weeded out harmful maladaptations and promoted 
> beneficial ones. There is nothing qualitatively different in random DNA 
> mutation or random methylation and so forth. They are both instances of 
> mutations in an organisms hereditary mechanisms. Why make one a first class 
> citizen and the other an interloper? 
> Naturally I am not arguing that epigenetic re-wiring is as permanent 
> or important as classic genetic based heredity; it certainly seems more 
> reversible for example.
> But isn't that the problem with epigenetic 'evolution'.  Evolution 
> requires faithful reproduction sufficient at least to create a local 
> breeding population.  My understanding of epigenetics is that it is 
> hit-or-miss after only a couple of generations.

"The methyl groups could become married permanently to the DNA, getting 
replicated right along with it through a hundred generations."


> Brent

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