Beyond The Genome: A Non-Reductionist Perspective On Development

Jonathan M:

I am using the term reductionism here in terms of DNA reductionism. The DNA sequence is not the sole determinant of embryonic development. A whole series of other factors are necessary — many of which are not reducible to the DNA level.

Yes indeed. I think most biologists would agree. I've recommended it before, but I'll do so again: Denis Noble's The Music of Life. http://www.musicoflife.co.uk/reviews.html Elizabeth Liddle

I don't know what "DNA reductionism" means that wouldn't encompass molecular genetics, imaging, and mutations. So, what factors in the Zhang paper were not reduced to the DNA level? We have the genetically encoded proteins of the hemidesmosome acting as sensors of tension (normally brought about through muscle-again genetically encoded proteins): "This pathway involves, in addition to a Rac GTPase, three signalling proteins found at the hemidesmosome. .... Tension exerted by adjacent muscles or externally exerted mechanical pressure maintains GIT-1 at hemidesmosomes and stimulates PAK-1 activity through PIX-1 and Rac. This pathway promotes the maturation of a hemidesmosome into a junction that can resist mechanical stress and contributes to coordinating the morphogenesis of epidermal and muscle tissues." DrREC

DrREC -

*Minor correction: You have the hemidesmosome and mechanosensor listed as separate complexes, where they are one in the same

Yes, you are right. I made the correction.

I’m quite puzzled by the warm inclusion of Zhang et al.’s paper in a post containing the phrases “Beyond the Genome” and “non-reductionist!”

I am using the term reductionism here in terms of DNA reductionism. The DNA sequence is not the sole determinant of embryonic development. A whole series of other factors are necessary -- many of which are not reducible to the DNA level. Jonathan M

I'm quite puzzled by the warm inclusion of Zhang et al.'s paper in a post containing the phrases "Beyond the Genome" and "non-reductionist!" I find this puzzling because their approach was both genetic and reductionist. They sought to understand the mechanosensing function of the hemidesmosome* by reducing it to its parts using molecular genetics and modern imaging methods. As this paper and others show, these and other mechanosensors aren't 'beyond the genome,' they are encoded by it! *Minor correction: You have the hemidesmosome and mechanosensor listed as separate complexes, where they are one in the same-- You: "in addition to the anchor point for epithelial cells known as the "hemidesmosome," there is a specialized device called a "mechanosensor" Abstract: "Our findings suggest that the C. elegans hemidesmosome is not only an attachment structure, but also a mechanosensor that responds to tension by triggering signalling processes." DrREC