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
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.
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