Nathaniel Comfort is identified by Wikipedia as “an American historian specializing in the history of biology. He is an associate professor in the Institute of the History of Medicine at Johns Hopkins University”. Comfort has written several books on the history of genetics, including a biography of Barbara McClintock, and I’ve heard he’s nearly finished what is likely to be the definitive biography of J. D. Watson. I have a great deal of respect for him.
Thus I was baffled by Comfort’s new piece in Nature discussing (or rather, dissing) Richard Dawkins’s The Selfish Gene. Despite that book’s influence and renown, Comfort claims that it’s outdated: indeed, not worth reading at all compared to books that discuss the view of evolution favored by Comfort. And Comfort’s favored view is that of the “Extended Evolutionary Synthesis” (“EES”), which argues that the “neo-Darwinian view of evolution” that fused natural selection and Mendelian genetics, is wrong and needs replacement with a new theory. I’ve discussed this view at length over the years (see my posts collected here), and, along with Doug Futuyma (see his article below), I note that while new discoveries have created add-ons to evolutionary theory (and dispelled some of Darwin’s own tenets, like the widespread inheritance of acquired traits), they don’t call for a new theory of evolution. The Selfish Gene is not outmoded—far from it.
In his essay, Comfort says that Dawkins’s view of evolution by natural selection as a process you can think of as driven by “selfish genes” is wrong: it’s too narrow and best left on the shelf. You can read Comfort’s piece here or by clicking on the title below:
As you may recall, Dawkins’s main point was that the unit of evolution by natural selection was the gene, or “replicator”: a bit of DNA that can reproduce itself from one generation to the next. The unit is not the individual, the group, or the species, but the replicator, which can be seen as “selfish” because those genes that replicate faster than their alternative forms will be the ones most represented in the the future. Faster replication can, for example, be effected by building bodies (“vehicles”) that last longer and leave more offspring than others. This is the main way we think of evolution by natural selection, but Dawkins’s “gene’s-eye view” is broader than this. Transposable genetic elements, for example, facilitate their own reproduction and survival by replicating quickly and infesting other parts of the genome. They spread through a species not by enhancing an organism’s adaptation, survival, or reproduction, but their own reproduction.
Further, as the book points out, a gene can spread by selection even if it reduces the survival or number of offspring of the bearer itself, but enhances the number of copies present in relatives or groupmates—via kin selection or reciprocal altruism. This view of natural selection can be thought of as the spread of “selfish” genes, but, as Dawkins asserts repeatedly, it need not lead to selfish or aggressive behavior of individuals—one of the most common misunderstandings of the book.
The gene’s-eye view influenced not just the public, but many biologists, including me, and it clarifies a number of points that were murky (e.g., kin selection). But Comfort says it’s narrow and outmoded. Take a look at Comfort’s second paragraph:
Re-reading it now, with decades of scholarship in the history of biology under my belt, it seems less benign. The determinism baked into the “gene’s-eye view” in the book troubles me, as does the passivity of the organism in Dawkins’s telling — a “vehicle”, a mere “replicator”. The implication: that traits such as aggression are hard-wired into people. Fortunately, over the past couple of decades, new tools, fresh models and scholars in many disciplines have begun to embrace the complex reality of biology. Readers in search of an understanding of life on Earth today would do better to reach for books that take a broader view.
Yes, in fact organisms are passive, for although they can influence the spread of replicators via their own behavior, those behavioral features are themselves the product of “selfish genes” (an example is “extended phenotypes”, like the beaver dam—one subject of Dawkins’s eponymous book). This is truly a deterministic, naturalistic process that has no room for “agency,” “will”, or teleology, though I’ve suggested that truly nondeterministic processes like quantum mechanics might influence evolution by producing mutations. Absent quantum effects, evolution is indeed deterministic, and organisms are vehicles that express the products of replicators. (Yes, I know that some physicists think quantum mechanics is deterministic in ways we don’t understand.)
As for the implication that selfish genes imply the evolution of aggression or other such behaviors, Comfort apparently hasn’t got Dawkins’s message.
So what is the “broader” view of biology that, Comfort argues, should replace that of the selfish gene? It is the “Extended Evolutionary Synthesis,” which calls for a wholesale rebuild of neo-Darwinian evolution because of things like epigenetic modification, “niche construction” (e.g., the beaver dam cited above), behavioral and morphological plasticity, and what is called “natural genetic engineering”, a quasi-teleological view, largely touted by James Shapiro, which claims that organisms engineer their own fates by some “intelligent” process that did not evolve in the Dawkinsian way.
As Doug Futuyma explains in his paper below, all the phenomena mentioned above, save “natural genetic engineering,” fit comfortably within the modern synthesis, even though some discoveries, like epigenetic modification of DNA, have been made in recent decades. (I’ll point out here that DNA modified by the environment can cause evolutionary change only insofar as it produces “selfish [modified] DNA that replicates faster than unmodified DNA. And we have almost no cases of epigenetic modification not themselves coded in the DNA forming the basis of evolutionary change.)
I’ll make just two more points; the first involving the “directionality” of evolution. Here’s more from Comfort’s piece:
For instance, neo-Darwinism teaches that evolution is a random walk through changing environments, with selection favouring whatever traits help an organism to survive. Today, many scholars argue that there has to be direction to evolution. In How Life Works (2023), for instance, journalist Philip Ball points out that in a single cell, there is an unfathomably large number of possible interactions between different kinds of molecule — and there are about 37 trillion cells in one human body. “Such a system,” Ball writes, “can only hope to be stable if, out of all this complexity, only a limited number of collective ways of being may emerge”. Living organisms are forced to evolve in those few directions.
And the neo-Darwinian idea of evolution as a random process seems to run counter to the unavoidable observation that life has evolved towards ever-greater complexity. Biochemist Nick Lane has argued that, right back to life’s origin, the main driver of this complexity is the second law of thermodynamics — entropy, the tendency toward disorder. “Energy-releasing chemical reactions are at the core of the living process of all organisms,” wrote he and others (W. F. Martin et al. Science 344, 1092–1093; 2014). The detailed chemistry behind this idea is outlined in depth in Lane’s brilliant 2015 book, The Vital Question. The overall idea is that complex life forms dissipate more heat than do their simpler counterparts. Life on Earth is pushed towards greater complexity and abundance because, given the composition of the planet, it is energetically favourable.
The first paragraph is in fact not a refutation of the selfish gene view. The only direction to evolution—and one that Dawkins notes—is that replicators get better and better at replicating over time. This in general leads to an increase in survival and reproduction of the “vehicles”—organisms—but it need not. The spread of transposable genetic elements, which account for a great deal of “genetic junk” that dominates our own genome, is one example. And nobody I know of thinks that organisms are unconstrained, either by their own nature or by the environment, in the way they can evolve. There are guardrails.
Second, the discussion of why life was once simple but has become more complex is not new. For one thing, life started out simple and thus if it was to go anywhere, it had to become at least a bit more complex. But the view of unidirectional complexity is simply not true. What is true is that life is a cumulative process, with new “adaptations” evolving from old ones, so a great deal of adaptive residue remains in our genome. But you’d be hard pressed to show that “complexity” has increased unidirectionally after we had multicellar organisms inhabiting many of the world’s niches. (By the way, each organism becomes or makes niches for other organisms, so evolution creates new ways of life, but that doesn’t mean that “life is more complex”).
Finally, there are many organisms that have evolved to become less complex, as replicators that “de-evolve” some features may be favored in some environments. Parasites are a common example. Tapeworms, for example, used to be free-living flatworms, but when they invaded the guts of organisms they lost most of their nervous and sensory systems, their digestive system, and their genomes became much simpler. Cave-dwelling organisms often lose their eyes: a decrease in complexity. Snakes used to be lizard-like organisms but have lost their limbs. Whales also lost their limbs. These examples are rife, and I won’t go on. The point is that Comfort is either distorting what Dawkins says, distorting what the Modern Synthesis says or implies, or distorting what’s happened in evolution.
Touting the EES, Comfort tells us above that there are better books to reach for than The Selfish Gene if you wish to understand where the theory of evolution stands. I would simply recommend Doug Futuyma and Mark Kirkpatrick’s high-level evolution textbook, simply called Evolution (Fifth Edition), published in 2022. To deal specifically with claims that the EES dismantles or greatly modifies the view of evolution in that textbook, you should read Doug Futuyma’s article below (click on the link). I’ve put its abstract below the title:
Abstract:
Evolutionary theory has been extended almost continually since the evolutionary synthesis (ES), but except for the much greater importance afforded genetic drift, the principal tenets of the ES have been strongly supported. Adaptations are attributable to the sorting of genetic variation by natural selection, which remains the only known cause of increase in fitness. Mutations are not adaptively directed, but as principal authors of the ES recognized, the material (structural) bases of biochemistry and development affect the variety of phenotypic variations that arise by mutation and recombination. Against this historical background, I analyse major propositions in the movement for an ‘extended evolutionary synthesis’. ‘Niche construction’ is a new label for a wide variety of well-known phenomena, many of which have been extensively studied, but (as with every topic in evolutionary biology) some aspects may have been understudied. There is no reason to consider it a neglected ‘process’ of evolution. The proposition that phenotypic plasticity may engender new adaptive phenotypes that are later genetically assimilated or accommodated is theoretically plausible; it may be most likely when the new phenotype is not truly novel, but is instead a slight extension of a reaction norm already shaped by natural selection in similar environments. However, evolution in new environments often compensates for maladaptive plastic phenotypic responses. The union of population genetic theory with mechanistic understanding of developmental processes enables more complete understanding by joining ultimate and proximate causation; but the latter does not replace or invalidate the former. Newly discovered molecular phenomena have been easily accommodated in the past by elaborating orthodox evolutionary theory, and it appears that the same holds today for phenomena such as epigenetic inheritance. In several of these areas, empirical evidence is needed to evaluate enthusiastic speculation. Evolutionary theory will continue to be extended, but there is no sign that it requires emendation.
No, evolution does not need a rebuild, and The Selfish Gene is not outmoded. It remains, for those who haven’t read it, a page-turner.
h/t reader John, who called my attention to Comfort’s article
