Richard Dawkins is without doubt the most eminent evolutionary theorist, and one of the most effective science communicators, of our age. The Selfish Gene (1976) was so influential that its gene-centric view of evolution is today widely accepted by scientists and the public alike. Like Charles Darwin’s On the Origin of Species, The Selfish Gene is one long and careful argument. Dawkins’ latest work, The Genetic Book of the Dead, is in contrast described by its subtitle as a Darwinian “reverie” and is more given to speculation than careful argument.
This is, Dawkins says, because our understanding of genetics is at such an immature stage that the subjects he wishes to write about cannot be dealt with solely through reference to existing studies. The book’s central tenet is that genes, when properly interrogated, can inform us of every past environment that an organism has ever inhabited. It also posits that a genome is “a bet that the future will not be too different from the past”. Dawkins is famous for his dismissal of both altruism and group selection – in which natural selection acts at the level of the group, rather than the individual or gene – in evolutionary processes, so as one reads The Genetic Book of the Dead, one waits with bated breath to learn about the kind of future that Dawkins envisions.
Some of the finest writing here concerns the description of the external appearances of cryptic species such as desert lizards or geckos that live on lichen-covered tree-trunks. Such creatures, Dawkins aptly says, wear their habitats on their backs. Only the great zoologist and artist Jonathan Kingdon (who grew up, like Dawkins, in Africa) surpasses Dawkins in this kind of close observation and description. But Dawkins goes further, stating that the external perfection we can see with our eyes in these camouflaged creatures must be matched with an internal perfection that has been just as concisely sculpted by evolution. Evidence for this, he believes, will be forthcoming as we unravel the language of the genes, which today remains as obscure to us as QR codes are to our eyes. At present, he says, “The easiest, if not the only, way to translate a human genome into a working body is to feed it into a very special interpreting device called a woman.”
Is the genome, Dawkins asks, like Koranic doctrine in that the most recent additions override the older ones? Or does it adhere to a primogeniture-like order? Insights come from turtles, which are unique in that they have been able to make the transition from water to land, and back again, repeatedly. Anatomy also sheds light. In mammals, the laryngeal nerve takes a long detour around an artery in the chest before looping upwards to serve the larynx. It cannot take a more direct path, Dawkins says, because “the major cost of radically reforming embryology” is greater than putting up with the inconvenience of a longer nerve route. In such cases, the older genes that control developmental process are evidently very hard to change.
Dawkins believes that the placement of every nerve and artery (and other elements of bodily structure) is precisely sculpted by evolution. Yet he does not discuss the condition known as situs inversus, which can cause the heart to be on the right rather than the left, without causing medical symptoms or complications. Such quibbling aside, it is easy to underestimate the power of natural selection even on the most obscure aspects of form or behaviour. The geneticist JBS Haldane (1892-1964) calculated how selection pressure so weak that it is not observable can nonetheless shape species. Natural selection functions by eliminating maladapted individuals. How long, he asked, would it take a selective force in favour of a new genetic mutation that removes only one in 1,000 individuals from a population to spread through half the population? For a recessive gene the answer is 321,444 generations. For species with short life-spans, that is just an eye-blink of geological time. This is important to palaeontologists, for it helps explain the abrupt appearance of many species in the fossil record (which is so incomplete that we almost never see evidence of short-lived events).
The Genetic Book of the Dead is on less certain ground when Dawkins analyses birdsong. He cites the “Beau Geste” hypothesis of John Krebs to explain the remarkable mimicry of the lyrebird, stating that “the bird with a large repertoire is pretending his territory is already occupied to the full”. This suggests that males sing to other males. Yet singing forms a vital part of courtship displays, which are directed at females. Moreover, when discussing doves, he states that the males “manipulate” females by singing, because females exposed to male songs experience “massive growth in a female’s ovary and oviduct… as though the male had the power to inject her with chemicals”. But it is in the interest of flying species to increase their bodyweight only when strictly required, so a female is likely to make that investment in enlarged reproductive organs only if breeding males are present. A female will still choose to mate with the male that most appeals to her, so this is hardly “manipulation”.
Dawkins refights old battles, for example, restating his opposition to Denis Noble, who wrote, “Genes are used. They are not active causes.” This is informative in as far as it dismisses some widespread misconceptions about genes. For example, some have argued that because genes can do nothing by themselves, they cannot be the focus of evolution. Dawkins’ riposte that genes exert selective pressure on their environment – other genes and the cell itself – is apposite.
There are some blind spots. For example, Dawkins states that “climate doesn’t menacingly change in response to biological evolution”. He forgets the case of “system engineers” like the humble waterweed Azolla arctica which 49 million years ago rapidly covered the Arctic Ocean, sequestering enough carbon in sediments to trigger a decline in atmospheric CO2 from 3,500 to 650 parts per million, thereby cooling the surface of the ocean from a balmy 130C to -90C. And the activities of our own species are currently forcing rapid warming which is well documented to have threatened many species, and even caused extinctions.
Perhaps the oddest reverie in this book of reveries concerns Dawkins’ thoughts on the naked mole rat. Like social insects, naked mole rats live in great colonies in which only a “queen” normally reproduces. As Dawkins points out, social insects have a winged reproductive class that disperses from the hive to establish colonies elsewhere. Dawkins posits that naked mole rats must give rise, on occasion, to hairy mole rats that can range widely over the Earth’s surface and set up new colonies. There is not the slightest shred of evidence for this idea, but perhaps that is the attraction of it. Dawkins is a fervent admirer of Darwin, who predicted in 1862 that a long-tongued insect must exist in Madagascar, because the Madagascan star orchid has long nectar tubes that require a pollinator. In 1903, when the long-tongued Wallace’s sphinx moth was discovered, Darwin’s intuition became legendary. Sadly, as a mammalogist, I do not think that Dawkins’ hairy mole rat will bring such acclaim, for it is almost certainly purely imaginary.
Dawkins spends two chapters explaining the “backward gene’s-eye view”. Through a process known as “genetic imprinting”, genes can “know” whether they came from a mother or father. Y chromosomes come from an immensely long lineage of male bodies – but, Dawkins writes, only a restricted subset of those male bodies. That’s because in some species a few males monopolise the matings: in one colony of northern elephant seals one male sired 121 of 348 offspring, while most males sired none at all. Females, on the other hand, usually have a single offspring per year. Why, Dawkins asks, don’t such species have far more females than males at birth? This would be economical, as all those frustrated bachelor males are an ecological waste.
The reason is that natural selection maintains a balanced sex ratio. If there are fewer males than females, then males have a higher chance of mating: natural selection will favour females that produce more males. And vice versa. “Equal sex ratio genes prevail,” writes Dawkins, “even though the society they create is horribly uneconomical.” I’m surmising here, but I think Dawkins would agree that the situation of the elephant seals is rather like that of imperial China, with its emperor and his immense harems, all guarded by eunuchs.
Dawkins’ last words in The Genetic Book of the Dead are: “You are the incarnation of a great, seething, scrambling, time-travelling cooperative of viruses.” It is hardly an attractive metaphor, and such assertions might help explain why people feel uncomfortable with some of Dawkins’ views. But another is surely the fear that in species like our own and elephant seals, “selfish genes”, over time, will inevitably lead to the establishment of brutal, patriarchal societies. One hopes for a better outcome.
An important test of Dawkins’ ideas lies in current demographic trends. Fewer and fewer babies are being born, particularly in societies where insufficient help is offered to mothers. Selfish genes are concerned with only one thing: getting into the next generation. So how could they have given rise to a “very special interpreting device” known as woman, with the ability to not reproduce and so defeat the genes’ ultimate aim as well as their patriarchal agenda? I would love to read Dawkins’ views on that.
The Genetic Book of the Dead: A Darwinian Reverie
Richard Dawkins
Bloomsbury, 360pp, £25
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[See also: Megalopolis’s bad history]
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This article appears in the 16 Oct 2024 issue of the New Statesman, Make or Break