Is the proposed Integrative Synthesis really new?
The article proposes a new synthesis which differs in four major respects from the traditional (modern) synthesis:
But is this really a new proposal? Havn’t we heard about the demise of neo-Darwinism too often?
“The full extent of this feedback from function to inheritance remains to be assessed, but it cannot be doubted that it runs counter to the spirit of the Modern Synthesis. The challenge now is how to construct a new Synthesis to take account of this development. In Table 1, I call this the Integrative Synthesis. I believe that in the future, the Modern Synthesis and the elegant mathematics that it gave rise to, for example in the various forms and developments of the Price equation, will be seen as only one of the processes involved, a special case in certain circumstances, just as Newtonian mechanics remains as a special case in the theory of relativity.”
The problems with the modern synthesis are that it is restrictive and that it is dogmatic.
“What went wrong in the mid-20th century that led us astray for so long? The answer is that all the way from the Weismann barrier experiments in 1893 (which were very crude experiments indeed) through to the formulation of the central dogma of molecular biology in 1970, too much was claimed for the relevant experimental results, and it was claimed too dogmatically. Demonstrating, as Weismann did, that cutting the tails off many generations of mice does not result in tail-less mice shows, indeed, that this particular induced characteristic is not inherited, but it obviously could not exclude other mechanisms. The mechanisms found recently are far more subtle. Likewise, the demonstration that protein sequences do not form a template for DNA sequences should never have been interpreted to mean that information cannot pass from the organism to its genome. Barbara McClintock deservedly gets the last laugh; the genome is indeed an ‘organ of the cell’.”
The idea of a more nuanced multi-mechanism synthesis is indeed not new. I am delighted, for example, to acknowledge the similarity of my ideas to those of Eugene Koonin (2009), Messoudi et al. (2013) and Laland et al (2013). The problem is that the dogmatism of neo-Darwinism has prevented open admission of the change. The change has already happened in the minds of those who listen to the experimental evidence.
Eugene Koonin, The Origin at 150: Is a new evolutionary synthesis in sight? Trends in Genetics, 25, November 2009, pp. 473-475. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2784144/
Eugene Koonin, Darwinian evolution in the light of genomics, Nucleic Acids Research, 37, 2009, pp. 1011-1034. http://www.ncbi.nlm.nih.gov/pubmed/19213802
Mesoudi A, Blanchet S, Charmentier A, Danchin E, Fogarty L, Jablonka E, Laland KN, Morgan TJH, Mueller GB, Odling-Smee FJ & Pojol B. (2013). Is non-genetic inheritance just a proximate mechanism? A corroboration of the extended evolutionary synthesis. Biological Theory 7, 189–195. http://link.springer.com/article/10.1007/s13752-013-0091-5
Laland, K. N., Odling-Smee, F. J., Hoppitt, W., and Uller, T. (2013) More on how and why: a response to commentaries, Biology and Philosophy DOI: 10.1007/s10539-013-9380-4.
Quotes from Koonin that resemble my text:
“In the post-genomic era, all the major tenets of the modern synthesis have been, if not outright overturned, replaced by a new and incomparably more complex vision of the key aspects of evolution.”
“The discovery of pervasive HGT [horizontal gene transfer] and the overall dynamics of the genetic universe destroys not only the tree of life as we knew it but also another central tenet of the modern synthesis inherited from Darwin, namely gradualism. In a world dominated by HGT, gene duplication, gene loss and such momentous events as endosymbiosis, the idea of evolution being driven primarily by infinitesimal heritable changes in the Darwinian tradition has become untenable.”
"The edifice of the modern synthesis has crumbled, apparently, beyond repair".
“The exclusive focus of Modern Synthesis on natural selection acting on random genetic variation has been replaced with a plurality of complementary, fundamental evolutionary processes and patterns.”
Laland et al (2013) also express many of the same ideas, and it is particularly important to note that they have also pinpointed the concept of causation as one of the problems:
“We (like many other developmentally minded evolutionists, e.g. West-Eberhard 2003) believe that resistance to these ideas derives in part from implicit models of causation that can channel thinking on these topics, leading to the neglect of potentially important explanations. For instance, in their recent review of phenotypic plasticity’s impacts on speciation, where extensive evidence that plasticity is evolutionarily consequential was presented, Pfennig et al. (2010, p. 459) nonetheless conclude that “recent reviews of speciation generally fail to discuss phenotypic plasticity, indicating that workers in this field do not recognize a significant role for plasticity in speciation”.”
which may be compared to my article:
“A central feature of the Integrative Synthesis is a radical revision of the concept of causality in biology. A priori there is no privileged level of causation. This is the principle that I have called the theory of biological relativity (Noble, 2008, 2012)…… Control is therefore distributed, some of which is inherited independently of DNA sequences. The revision of the concept will also recognize the different forms of causality. DNA sequences are best viewed as passive causes, because they are used only when the relevant sequences are activated. DNA on its own does nothing. The active causes lie within the control networks of the cells, tissues and organs of the body.”
Laland et al also compare their position with the Modern Synthesis in the form of a table:
The compatibility of this table with my own is obvious. I do not claim any priority in expressing my ideas and I am delighted to discover others who see the evidence in much the same way. Where I have gone a little bit further is in pointing out how physiology comes back onto centre stage as the study of function: “the organism should never have been relegated to the role of mere carrier of its genes.”
|The MUSIC of Life: Biology Beyond the Genome ©Denis Noble|