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.”
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The MUSIC of Life: Biology Beyond the Genome ©Denis Noble |