What is the Extended Evolutionary Synthesis?

Continuing the discussion from The "Third Way"/EES and Population Genetics:

@sygarte, any interest in hashing this out? I think you are largely right…

We’ve talked about this in the past, but never really online. The problem I have is not with the science, but with the self-serving pseudohistory that they construct about evolutionary science. I don’t disagree with the EES, but just think it is merely just modern “evolutionary science.”

I’m not calling you out to just argue. Rather, the conversation between us might benefit others to listen in on. If you are up for it, come play with me on this thread. :smile:

Actually, I have been thinking about this more since our last exchange. One of the things I have not mentioned, either here or elsewhere is the important emphasis coming out of Evo Devo and epigenetics on gene expression control as a major factor in evolutionary change. I know that there is nothing new in the biology of gene expression that evolutionary biologists are not familiar with, but the point is that allele frequency, which is a measure of the number of specific alleles in a population gives only a rough estimate of potential fitness or selective advantage. A really great allele that is never expressed isnt much use. Just as neutral theory (See Josh’s other new thread) sort of put the kabosh on adaptationism (as long advocated by Gould), findings that gene regulatory network mutations have more to do with major changes in body plans than any structural gene allele, are calling into question the whole concept of structural gene mutations as the major driver of variation leading to evolution.

What I would like to know from you Josh, not being at all up in the field, is whether current models for population genetics take into account gene expression variability. My impression is that they do, but I dont know the details.


At minimum, to the extent that mutations in DNA affect gene expression variability, this absolutely accounted for in population genetics. The fact that some mutations cause their effect by changing expression is already part of population genetics. One important fact is that gene regulatory sequences can function like “dimmer switches” that do not solidly turn on or off a gene when they are mutated. That makes it safer to build up variation this way.

Here, when I say “mutations”, I’m not meaning merely point mutations, but a whole host of different mutations (e.g. transposon jumping, copy number variation, structural variation), all of which can dim in or dim out expression of genes at different point of development. This is all included in the theory, but not always modeled in practice. Part of the reason why is that we do not have enough knowledge of some of the particulars yet (e.g. de novo mutation rate). Give it time though. It is already part of the theory. Soon enough there will be software out there to model it with increasing detail.


My view is very similar (though not exactly the same) as Larry Moran. Ignore the anti-Templeton posturing and read this:

I don’t object to work on those subjects. My beef is with the idea that they pose a problem for our current understanding of evolutionary theory. More importantly, my main complaint is that the biologists who will spend all this money missed the real revolution that took place 50 years ago.


But my real beef is with the outdated view of evolution held by EES proponents. To a large extent they are fighting a strawman version of evolution. They think that the “Modern Synthesis” or “Neo-Darwinism” is the current view of evolutionary theory. They are attacking the old-fashioned view of evolutionary theory that was common in the 1960s but was greatly modified by the incorporation of Neutral Theory and increased emphasis on random genetic drift. The EES proponents all seem to have been asleep when the real revolution occurred.

When you listen to them, you get the distinct impression they have never read The spandrels of San Marco and the Panglossian paradigm: a critique of the adaptationist programme. I have no confidence in biologists who want to overthrow a view of evolutionary theory that’s already been dead for half a century. I have no confidence in biologists who aren’t at ease talking about non-adaptive evolution. This is the 21st century.

That is exactly my complaint with both them, and the Dissent from Darwinism (https://dissentfromdarwin.org/). No informed scientist is a scientific Darwinist any more. That is a long falsified theory. Any time the term “Darwinism” is being thrown around in reference to our current understanding of evolution, you know it’s someone uninformed or with an agenda (usually for atheism or against evolution).


And to learn about neutral theory, read here:

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