Sunday, January 11, 2009

on to meta-Lamarckism?

Ted Steele at the launch of his book lamarck's signature

Anchsluss: Generally the term used for the merging of Austria into greater Germany in 1938, which was a stepping stone for other incorporations or annexations [the Sudetenland in Czechoslovakia, the Memelland in Lithuania] prior to WW2.

Neo-Lamarckism, etc continued

Arguably this is a minor error – Weismann certainly did propose that the germ cells alone [the gametes] were the carriers of inheritance [he wouldn’t have called it genetic inheritance], influencing the formation of all the somatic cells to follow, but unable to be influenced by them. Lamarckian evolution must require changes in somatic cells to be transmitted to the germline. The Weismann barrier, if it exists, specifically rules out such transmission, thus ruling out the possibility of Lamarckian evolution.

Dawkins doesn’t explicitly mention the Weismann barrier in his attempted refutation of Lamarckism. He takes a different tack, referring to two ways of looking at the relationship between the germline and the fully fledged organism, preformationism and epigenesis, which he in turn describes as the blueprint model versus the recipe model - and basically he characterizes the preformationist/blueprint model as wrong. 

The idea is that the blueprint model argues that the germline cells somehow contain a blueprint or one to one correspondence for the differentiated somatic cells that are generated from them, whereas the correct model sees those cells as containing a recipe for that differentiation. 

Epigenesis dates back, in most rudimentary form, to Aristotle, but fell out of favour with the dominance of Christian creationism, and the different ways of understanding the problem are still infected by metaphysical/religious biases:

where preformation stated that the germ cells of each organism contain preformed miniature adults that unfold during development, epigenesis held that the embryo forms by successive gradual exchanges in an amorphous zygote. Although both traditions tried to explain developmental organization, religious and metaphysical arguments on the conception of embryonic matter as either active or passive determined the scope of their respective explanations. It is shown that these very arguments still underlie the use of gene-centric metaphors in the molecular revolution of the 20th century. 
Dawkins's argument is that Lamarck's theory relies on a preformationist version of embryological development. As he puts it,

Embryonic development is a process, in which all working genes participates; a process which, if correctly followed in the forward direction, will result in an adult body; but it is a process that is inherently, by its very nature, irreversible. the inheritance of acquired characteristics not only doesn't happen: it couldn't happen in any life-form whose embryonic development is epigenetic rather than preformationistic. 
Dawkins is clearly relying here on the Weismann barrier, which Ted Steele is claiming, at the very least, isn't as absolute as once thought. He's claiming that a new meta-Lamarckism, incorporating both Lamarckian and Darwinian principles, will provide our best understanding of more rapid evolutionary development. Steele's theory of reverse transcription from the somatic cells to the germline, which has of course proved very controversial and has stifled his career as a molecular immunologist through the eighties and nineties, has received some research support in recent years, with Drs Corrado Spadafora and Patrick Fogarty both independently verifying the inheritance of non-germline genetic information - in mice in Fogarty's case, and in 30 diverse species according to Spadafora. Obviously, I'm no scientist and it would be better to follow the research data yourself [anyone who ever reads this], but I may write again about this intriguing issue in order to master it to some limited degree. 



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