I first read The Selfish Gene as a graduate student in neurobiology and animal behavior in the 1980s. I was impressed by biologist Richard Dawkins’s clear distillation of mid-20th-century evolutionary biology. Decades later, after studying the history of biology, I see the 1976 book differently: its gene-centered determinism and portrayal of organisms as passive “vehicles” for “replicators” overlook the complexity of life. New tools, models and research across many fields now offer a broader understanding of how biology changes.
The book’s central idea is simple: living organisms are ways for genes to produce more copies of themselves, which can then be passed through generations.
Dawkins’ paradox: dissecting the body’s fight to suppress selfish genes
When it appeared, The Selfish Gene seemed relatively uncontroversial. Dawkins’s ideas aligned with mainstream sociobiology, and the book presented concepts similar to those being taught by my instructors.
Rereading it now, the book’s “genetic perspective” is more troubling. Its determinism, along with Dawkins’s description of organisms as passive “vehicles” and mere “replicators,” can suggest that traits such as aggression are hardwired into people. Fortunately, research over the past several decades has embraced more complicated accounts of biology. Readers seeking to understand life on Earth today would benefit from works that take a broader view.
Gene-centered thinking
The Selfish Gene represented the culmination of the “modern evolutionary synthesis.” This framework uses mathematics to describe evolution at the population level by tracking changes in the frequency of different versions of genes, known as alleles, across time and space.
Dawkins wrote that the book’s genetic perspective was “implicit” in the 1930s work of modern-synthesis pioneer Ronald Fisher and his contemporaries, but was made “explicit” by evolutionary biologists George Williams and William Hamilton in the 1960s. “To me, their insight struck me as prescient,” he wrote, “but I felt it was too succinct and not expressed powerfully enough.” The Selfish Gene then pushed that idea to its limits.
Richard Dawkins’ Book of the Dead is haunted by the ghosts of his past works
The modern synthesis brought together two fields: neo-Darwinian evolution and Mendelian genetics. Neo-Darwinian evolutionary theory was established by biologist August Weismann in his writings of the 1890s, including Die Keimplasma (Germ Plasm).
In On the Origin of Species, Charles Darwin set out the central principle that living things evolve over many generations through natural selection. In each of the five editions published between 1859 and 1872, however, Darwin increasingly accepted the “effects of use and disuse”—an idea associated with naturalist Jean-Baptiste Lamarck, which held that traits acquired during an organism’s life could be inherited.
Darwin used blind cavefish (Astyanax mexicanus) as an example. Their ancestors had eyes when they first entered lightless caves, but after many generations of disuse, the eyes degenerated and the changes gradually became inherited.
Darwin did not explain why his theory could accommodate such phenomena, nor did he propose a mechanism. Today, evolutionary biologists might argue that animals that spent less energy than their neighbors developing complex but useless structures, such as disused eyes, could devote that energy to larger gonads or territory defense and thereby gain a survival advantage.
For Weismann, however, incorporating use and disuse into Darwinism was a dangerous move toward teleology that risked handing explanations of biological change back to bishops and mystics. He proposed that only germ plasm—the material contained in sperm and egg cells—passes from parent to child, and that nothing outside it can influence what is transmitted.
A tray containing the entire human genome divided into over 20,000 DNA fragments.Credit: James King-Holmes/SPL
The second component of the modern synthesis, Mendelian genetics, was developed not by its namesake, the 18th-century monk Gregor Mendel, but by naturalist William Bateson in a strange and brilliant 1902 book, Mendel’s Principles of Heredity: A Defence.
Mendel experimented with breeding peas and published a paper in 1866 describing patterns of inheritance—for example, how many green and yellow offspring might result from crossing green and yellow peas. We now know that only some traits controlled by single genes follow the simplified pattern he observed.
Mendel cautiously claimed to have discovered “laws that are valid for … Pisum,” the genus of peas. Bateson argued instead that all heredity followed Mendel’s laws. His book defended the theories of his rival and former close friend, Walter Weldon.
Weldon argued that such neat and simple laws could not explain how nature works. He pointed out that traits such as height vary continuously in a bell-shaped, normal distribution and argued that these traits are influenced by many factors, including both genetic and environmental influences.
As historian Gregory Ruddick has argued, Mendelism ultimately became widely accepted for pragmatic reasons rather than because it captured an essential truth. It was easy to teach and methodologically simple.
A new biology
Both strands of the modern synthesis treated genes as the sole determinants of heredity, and both had achieved near-universal acceptance well before Dawkins’s book appeared. The disputes and confidence of their proponents helped keep challenges and alternatives at bay.
To historians, that universal acceptance can sound almost ideological. Fortunately, scientists’ understanding of the fundamental mechanisms driving evolution has changed dramatically since The Selfish Gene was published.
Source: www.nature.com
