Hopper or locust?
This morning Aeon published a revised version of my story “Die, Selfish Gene, Die,” which originally ran last Tuesday. The title is the same, the subtitle altered:
Die, selfish gene, die
For decades, the selfish gene metaphor let us view evolution with new clarity. Is it now blinding us?
In the original (as in the revised) I argued that the “selfish gene” model and meme popularized by Richard Dawkins’ lovely book, The Selfish Gene, is outmoded and threatens to impoverish the way both scientists and the rest of us view genetics and evolution.
I didn’t expect to convince everyone this is the case, and I haven’t. But I had hoped to make my argument clear, and soon after the story’s publication I saw that I had not. Quite a few readers were confused, and others misunderstood me. For this I apologize. I take seriously and highly value my readers’ efforts to understand what I write; I’m deeply sorry if even a few well-meaning readers tried and failed to take my meaning because I muddled it. In this case it was more than a few.
Thus the revised and expanded article posted this morning, which seeks to clear up the main muddles. I also added a version highlighted and one with links. Here’s a guide:
- The expanded version is here at Aeon.
- The original is archived here.
- If you primarily want to see the most substantive additions and alterations (because you’ve already read the original), I’ve supplied a PDF in which those sections are highlighted. (Note: That document highlights probably 80-90% of the changes, and all the most vital, but not quite a few smaller ones that go along the same lines. It may also have a few small differences from the published version. Please don’t quote from it without checking against the latest published version.)
- And here is a version with links to sources and such (which don’t appear in the Aeon version).
Above all, the revision also seeks to make dead clear a point that I failed to make emphatically enough the first time around:
I am not saying that the all the science described or suggested by the ‘selfish gene’ model is wrong. I am observing that while the selfish gene story is adept at taking in new findings and ideas from genomic studies, anthropology, and other evolutionary studies, it does so these days with increasing discomfort to both host and guest. And I am asking, in an age when such new ideas and discipines are flourishing and new tools are revealing astounding new things about the genome, whether the selfish gene story remains the best way to account for or inspire them.
As I put it in the revised article:
Does it make sense to attach these proliferating findings and ideas to the selfish-gene story as appendices? Or is it time to find another story? It may be that the gene is always a player. But it is rarely the only player. And — may I speak metaphorically? — it may (or may not) be that the gene always behaves as if it were selfish. But that doesn’t mean it always gets its way.
The story has small changes scattered throughout. The most extensive additions and changes in two places:
- in the section starting with “Like what other ways?” and ending with the paragraph quoted above. This added section looks at research areas I argue are in tension with the selfish-gene model. Their absence allowed many people to conclude I was offering another single dynamic, genetic accommodation, as a global replacement to conventional genetic selection.
- In the “fast hunter” section about genetic assimilation (called genetic accommodation in the original; assimilation is more exact, since in some usage it’s one kind of accommodation). This passage starts with “One way in which the gene follows…”. The main new emphases here are that the process is most definitely not Lamarckian, and that genetic assimilation is just one example (along with the many named in change #1 above) of a dynamic does not fit comfortably within the selfish gene story.
Again: You can find those spots most easily if you consult the PDF in which they are highlighted. I hope these passages clarify things for any readers that the original confused or misled. If not, please read the whole thing, for the many smaller tweaks I’ve made address these issues too.
Thanks for reading.
Comment policy: As always, free, civil discussion of ideas is welcome, while insults or ad hominem attacks are not. Discuss ideas and arguments, not their vehicles. Thanks.
Photo by scarymonkeyshow. Some rights reserved.
David: You’ve got the wrong Eva Jablonka. The one you mean is not professor of math education (?!) in London but professor at Tel Aviv University and a renown evolutionary biologist.
Ah! Thanks so much. That ID got inserted during fact-checking and I’d failed to notice it. Will fix now. Much obliged.
I am little surprised that you ignored my comment about Diana’s story. I was trying to be helpful, but maybe I was not clear. As I read it, what you describe is not genetic assimilation (GA) but standard natural selection. Diana’s ancestors seem to be irrelevant. She has a beneficial mutation just when it’s needed; therefore it gets passed on multiplicatively. You even say “[Diana runs faster than her fastest siblings and cousins ever could [because of that mutation].” So what does it matter whether her ancestors ran extra hard and changed their gene expression? She’s the one who lucked out. The fact that she ran hard before was irrelevant to the mutation. (Hey if it were, that would be Lamarckian!)
I think the problem with your explanation starts here: “Several generations down the line, a beneficial mutation occurs…” In GA, the mutation would have to come first. It is hidden (because of Waddington canalization) until an environmental change triggers the expression of the gene in question. Then via selection, that (previously inactivated) gene is made to multiply until its expression is possible even without the original environmental stress. (That’s the part no one really understands: the under-stress selection process must cause serious regulatory network rearrangement in development to allow the silent gene to become active in a heritable fashion. How that really works is a mystery. The Lindquist lab at MIT and Tabin lab at Harvard are the go-to places for more on that.) In your story the genome changes (Diane’s lucky mutation) but in GA, it does not: the change is entirely epigenetic (and environmental). Also the real punchline is that Diana’s descendents will remain fast runners even when the need for running disappears. That’s what’s amazing about GA.
Final point: GA destroys the selfish gene meme. The fact is, a brandnew trait appears that becomes reliably heritable with absolutely no change in the genome. In fact one can imagine a world (in science fiction of course) where all the genome is fixed and immutable with no variability of any sort, and yet evolution would occur, with natural selection operating entirely at the level of epigenetics and the heritability would involve regulatory networks. I don’t believe that world can exist but I know that theoretical biology cannot disprove it. Whereas a world where water freezes when you put it in a hot oven is one that physics can disprove.
Just a short pingback to say two things:
1) I am impressed by your effort and dedication, I really am. The “additional material” you publish here is a shining example of how scientific journalism should be done. I also agree that we need to make the complexity of evolutionary biology more widely known.
2) I am still disagreeing with the more scientific side of your argument, and I can’t live with it, so I’ve published another comment here.
Comment and criticism are welcome.
Keep up the good work,
Sergio
Thanks, Sergio. Greatly appreciate your reconsideration, and your quite nice post.
Sergio:
The link to your comment did not work. Can you please send it again.
Oh, sorry,
didn’t check it!
This
http://sergiograziosi.wordpress.com/2013/12/14/more-on-the-selfish-gene/
should work.
The December 13 2012 Science articles on cavefish variation, courtesy of Heat-Stress Protein 90 [HSP90], are a fascinating example of morphology beyond the gene’s direct control. Here in a cave’s darkness is a beautifully controlled natural experiment.
The stress of a cave’s salty water overloads the repressive genetic police state run by HSP90. The prison gates are opened, and creative genius long repressed is released to freedom.
That creative genius tries experiments too bold for the old repressive regime–it experiments with eyesight, with the little fish’s vital ability to see the world around it. Those bold experiments reveal an unimaginable truth — in the kingdom of the blind, the eyeless fish is king. Eyes are a useless burden in perpetual darkness, while other senses become far more valuable.
This is an elegant and clear example of nature’s creativity, an example perhaps compelling enough to compete against the Selfish Gene. Shutting off the Repressor of Hidden Genetic Abilities is an image that should resonate well with our Western cult of repressed, unrecognized genius and its uncomfortable relationship with the Big Control Systems of government and corporations. Yes, this fish story contains a metaphor with legs — or rather, fins.
It’s a pleasure to share enthusiasms for matters scientific, I quite enjoyed your piece’s honest search for balance in a world of dogmatic simplicities. Popular scientific journalism such as Dawkins’ and yours is (cryptically) powerful in shaping public understanding, research agendas (and funding?). In time, even this balanced perspective will become a new dogmatism in its own right…
[ Cryptic Variation in Morphological Evolution: HSP90 as a Capacitor for Loss of Eyes in Cavefish
Science 13 December 2013: 1372-1375. Also Science 13 December 2013: 1304. ]
Thanks, Rick, for this contribution and a nice recognition of the sort of reframing I am after.
What you are actually implying isn’t at all the death of the selfish gene theory – BUT MAKES DAWKINS’ CASE EVEN STRONGER! It shows that The-Genes-That-Made-It-Through-The-Ages are not only amazingly stable, but also ingeniously adaptable! Wow! A gene can survive in a cow, in a human, or an earthworm – it doesn’t care WHAT it helps building, as long as it works as a vehicle for it’s survival through eternity. A certain group of little die-hard fighters. And how much stronger even, when these genes can be turncoats, opportunists – have evolved to have a plan B! This gives dawkinsian selfishness a new dimension – instead of disproving anything, this is a new layer to explore! Awesome.