Some thoughts about Epigenesis and ID.
This was inspired by a short dicussion on Uncommon Dissent.
1) Epigenetics (non-genetic inheritance) is fascinating and important, but keep a sense of proportion. Mendelian/DNA based inheritance is understood in great detail, accounts for an enormous amount of what we observe in the way of inheritance, supports detailed predictions, and even allows us to control inheritance to a limited extent. None of this true of epigenesis. There is no reason to believe that epigenesis is more fundamental or in some way controls genetic inheritance. It is more likely to be just one of those heath robinson additions to the process going on in parallel that evolution inevitably produces. It works - so it remains.
2) You could imagine that epigenesis might be the route for some Lamarckian inheritance to take place. For example, the individual uses certain functions a lot and this increases the amount of mRNA created for the proteins required to support those functions, and the RNA in some way gets inherited even though the DNA responsible for the mRNA in the first place is not inherited. (It might even eventually affect the DNA of the germ line of the offspring). There is nothing designed or teleological about this - unless you think of the organism itself as the unconscious designer. (This is probably complete biochemical rubbish - it is the just the logic I am trying to illustrate.)
3) Lamarckian inheritance means that some variation is not random but is also not designed. This makes all estimates of the probability of certain proteins arising through random mutation irrelevant.
1) Epigenetics (non-genetic inheritance) is fascinating and important, but keep a sense of proportion. Mendelian/DNA based inheritance is understood in great detail, accounts for an enormous amount of what we observe in the way of inheritance, supports detailed predictions, and even allows us to control inheritance to a limited extent. None of this true of epigenesis. There is no reason to believe that epigenesis is more fundamental or in some way controls genetic inheritance. It is more likely to be just one of those heath robinson additions to the process going on in parallel that evolution inevitably produces. It works - so it remains.
2) You could imagine that epigenesis might be the route for some Lamarckian inheritance to take place. For example, the individual uses certain functions a lot and this increases the amount of mRNA created for the proteins required to support those functions, and the RNA in some way gets inherited even though the DNA responsible for the mRNA in the first place is not inherited. (It might even eventually affect the DNA of the germ line of the offspring). There is nothing designed or teleological about this - unless you think of the organism itself as the unconscious designer. (This is probably complete biochemical rubbish - it is the just the logic I am trying to illustrate.)
3) Lamarckian inheritance means that some variation is not random but is also not designed. This makes all estimates of the probability of certain proteins arising through random mutation irrelevant.
posted by Mark Frank at 9:11 am
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