Saturday, September 05, 2009

Lamarckianism Strikes Back

Is Lamarck making a comeback? The French biologist Lamarck argued that traits acquired by parents in their interactions with the environment were passed on to their offspring. Darwin argued, rather, that changes in heritable traits were what were passed on, and those changes came about via mutations, which were selected for in the environment. There was no direct influence from the environment in the Lamarckian sense. While cultural memes could be argued to follow Lamarckian evolution, certainly biological traits do not.

And then epigenetics was discovered. It turns out that patterns of gene regulation can be established based on the organism's interactions with the environment, and that those patterns of regulation can be passed on. This seems to have been a recent discovery -- but, as it turns out, it is not. In the early 20th Century, a Lamarckian biologist, Paul Kammerer, did experiments with midwife toads that made them become aquatic within a generation or two by placing the first generation in constant aquatic conditions. According to Darwinian theory, that should not happen.

Of course, this is not at all inconsistent with Darwin, if you understand gene regulation. Entire genes can be turned off if not necessary. This is hardly inconsistent with Darwin -- but it is also consistent with Lamarckianism. With the combination of digital Darwinism (mutations changing genes) and analog Lamarckianism (passing on of epigenetic traits acquired in the environment), it seems that we have digital-analog genetic inheritance and evolution. Which is what we would expect in a digital-analog world (I argue that the world is precisely such in both my dissertation and in my book "Diaphysics").
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