Wednesday, 1 September 2010

Lamarck again

I keep thinking about evolution and would like to have the time to explore all things Lamarckian a bit more. This is definitely crucial in the paleo context and it seems that thinking in the paloesphere has been limited to Darwinian theory.

Here is a popular text from Newsweek. Preciusly I also cited an article on Lamarkian medicine. Recently medical relevance of Lamarck's theory has been highlighted again. I also recommend this paper, a good overview of the problem, which also gives credit to Darwin for his "Lamarckian" theory of pangenesis.

If I had the time I would also read Ross Honeywill's book, which clearly looks interesting, though it has to be shipped from Australia.

Understanding this is absolutely essential as it is conceivable that some of us are already adapted to Neolithic food/lifestyle and changing back to paleo could actually be maladaptive! Or perhaps Lamarkian mechanisms allowed adaptation but only suboptimal, relevant to reproductive success, but not optimal for, say, vitality and longevity. It would be different in different populations and even individuals and we would need to find out empirically what works best, though we have only one life for the experiment.

Apparently, some characteristics become inherited after 5-10 generations and this is known as Baldwin effect. Importantly, inheritance requires some compensatory mechanism, such as hypertrophy after exercise or activated metabolic pathway after change in diet. Simple cutting of rats' tails would not make their offspring be born without tails (same with circumcision).

I guess one place to look for would be polymorphisms in metabolic enzymes in populations with different exposure to Neolithic agents.

Can all breeds of dogs be switched to a diet suitable for a wolf? Would that affect their fertility, health, life span? [Dogs have been fed meat and bones for most of the history with grains introduced very only recently, but grains were always cheaper than meat...].

How about polar bears, can they go on a grizzly diet? Polar bears are very relevant, as they apparently switched to a completely different diet during some 10K years! But in this respect Italian wall lizard is even more impressive, whether it was Lamarck or Darwin at play.

It is pure heresy, but this is what is making it so fascinating, particularly if you have read Paul Feyerabend or Thomas Kuhn.

Think of the societal implications.

But natural selection could also work during relatively short time, as in the case of Tibetans and their adaptation to high altitude.

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