Genome complexity in embryology (Introduction)

by David Turell , Thursday, April 23, 2015, 01:45 (3288 days ago) @ David Turell

Development of form in the embryo is not dictated by the genes, according to Michael Denton!:-"In addition, it is well established that the embryo is shaped by epigenetic biophysical and biomechanical forces and NOT by the genes. Yes, the genes provide the raw material -- base matter -- but it is the shaping of this raw matter by physical forces that gives us the specific architecture of the embryo. These forces arise from the emergent viscoelastic properties of individual embryonic cells and cell collectives -- layers of cells, clumps of cells, etc. Self-evidently the physical properties of one cell (the initial egg) are very different from the physical properties of a ball of cells (the morula), and a hollow ball (blastula) has different properties again.-"This succession of unique physical properties in the developing embryo that occurs during ontogeny is not specified in the genome. What is also very intriguing about the biophysical and biomechanical forces that shape embryos is that they represent a clear case of top-down causation where the overall biomechanical state of the embryo influences downwardly the behavior and state of all the constituents in the embryo. Even the expression of genes is now known to be regulated to a degree by the mechanical state of the whole embryo itself and its constituent cells. Hence my interest in Aristotle's substantial agencies, which shape "base matter" into the higher architecture of life." (my bold)-http://www.evolutionnews.org/2015/04/aristotle_redis095391.html