It is a peculiarity of history that the foundations of modern biology – and, as a consequence, some of the worst atrocities of the twentieth century – have to depend so much on peas. Think again about school biology and Gregor Mendel, whose 200th birthday we are celebrating next month. Although Mendel is invariably described as a monk, his formidable legacy is not in Augustinian theology, but in the main science of genetics.
In the mid-19th century, Mendel (whose real name was Johann – Gregor was his Augustinian denomination) raised more than 28,000 pea plants, crossing tall with short seeds and wrinkles with smooth flowers and violets with white flowers. What he found in that forest of pea plants was that these traits were segregated in the offspring and not mixed, but re-emerged in predictable proportions. What Mendel had discovered were the rules of inheritance. Characteristics were inherited in discrete units, what we now call genes, and the way these units flowed through pedigrees followed clear mathematical patterns.
These rules are taught in every high school as a basic part of how we understand fundamental biology: genes, DNA, and evolution. We also teach this story, because it’s a good story. Mendel’s work, published in 1866, was being made while Darwin was working on his best idea. But this Moorish monk genius was ignored until both men were killed, only to be rediscovered in the early ninth century, which solved Darwinian evolution with Mendelian genetics, ushering in the modern era of biology.
But there is a lesser known story that shaped the course of the twentieth century in a different way. The origins of genetics are inextricably linked to eugenics. Since Plato suggested “high-quality” parental mating and Plutarch described Spartan infanticide, the principles of population control have been in place, probably in all cultures. But in the age of Victorian industrialization, with a constantly expanding working class, and Darwinian evolution, Darwin’s half-cousin, Francis Galton, added a scientific and statistical brilliance to the deliberate sculpture of society. , and called it eugenics. . It was a political ideology that co-opted the new and immature science of evolution and became one of the most defining and deadly ideas of the twentieth century.
All new scientific discoveries exist within the culture in which they are born, and are always susceptible to abuse
The United Kingdom was on the verge of involuntary sterilization of the “undesirables” as legislation, something that Churchill campaigned firmly during his years in the Asquith government, but which MP Josiah Wedgwood resisted with success. In the United States, however, eugenics policies were enacted beginning in 1907, and for most of the next century in 31 states, an estimated 80,000 people were sterilized by the state in the name of purification.
American eugenics was faithfully married to Mendel’s laws, although Mendel himself had nothing to do with these policies. Led by Charles Davenport, a biologist and devotee of Galton, the Eugenics Record Office in Cold Spring Harbor, New York, set out in 1910 to promote a racist and empowering ideology and to reap the genealogies of Americans. With this data, Davenport imagined, they could establish the legacy of both desirable and defective traits, and thus purify the American people. Thus they could fight against the imagined threat of a great theory of substitution facing white America: undesirable people, with their undisciplined fecundity, will propagate inferior genes and the ruling classes will be wiped out.
Pedigrees were an important part of the American eugenics movement, and Davenport had feverishly clung to Mendelian heritage to explain all sorts of human weaknesses: alcoholism, crime, mental weakness (and, strangely, a tendency to navigate). . Inheritance, he wrote in 1910, “is the only great hope of the human race; his savior from imbecility, poverty, disease, immorality, ”and like all enthusiastic eugenicists, he attributed the inheritance of these complex traits to genes: nature above food. It is from Davenport that we have the first genetic studies of Huntington’s disease, which is strictly due to a Mendelian inheritance, and the color of the eyes, which, despite what we still teach in schools, is not.
Deborah Kallikak, the young woman whose family history Henry Goddard invented to support her theories. Photo: Macmillan & Co. Publishing 1912
A particular story from this period stands out. Psychologist Henry Goddard had been studying a girl under the pseudonym Deborah Kallikak at his New Jersey clinic since the age of eight. He described her as a “weak-minded person, the idiot, the criminal, the kind of girl or woman who fills our reformatories.” In order to trace the origin of his problems, Goddard produced a detailed pedigree of the Kallikaks. He identified as the founder of this bloodline Martin Kallikak, who stopped on his way home from the war of independence to his Quaker wife to conceive a “weak but attractive waitress” with whom he did not go. have more contact.
In Goddard’s influential 1912 book, The Kallikak Family: A Study in the Heredity of Feeble-Mindedness, he drew a perfect pattern of Mendelian heritage for good and bad traits. The legitimate family was eminently successful, while their bastard offspring produced a clan of criminals and “defective” disabilities, which eventually ended with Deborah. With this, Goddard concluded that the mental weakness of the Kallikaks was encoded in a gene, a single unit of defective inheritance that was passed down from generation to generation, just as in Mendel’s peas.
A contemporary geneticist will do wrong for many reasons. The first is “weak-minded” terminology, which was a vague, pseudopsychiatric diagnosis that was supposed to include a wide range of current clinical conditions. We could also reject his Mendelian conclusion on the basis that complex psychiatric disorders rarely have a single genetic root and are always deeply influenced by the environment. The presence of a particular gene will not determine the outcome of a trait, although it may contribute to its probability.
This is a modern understanding of the extreme complexity of the human genome, probably the richest data set in the known universe. But not even a thorough contemporary analysis is needed in the case of the Kallikak, because the waitress never existed.
The Kallikak Family Tree, from a 1955 textbook. Photo: Macmillan & Co Publishing 1912
In fact, Martin Kallikak’s legitimate family was full of famous triumphs: men of medicine, laws, and clergy. But Goddard had invented the illegitimate branch, mistakenly identifying an unrelated man named John Wolverton as the bastard son of Kallikak, and dreaming of his mother a waitress. Wolverton’s descendants included people with disabilities, but photos from Goddard’s book show some of the children with facial features associated with fetal alcohol syndrome, a condition that is largely determined not by genetic inheritance but by exposure. at high alcohol levels. in the womb. Although the family tree was completely false, this case study remained in psychology textbooks until the 1950s as a model of human inheritance and as a justification for forced sterilization. The Kallikaks had become the founding myth of American eugenics.
The German eugenics movement had also begun in the early 20th century and grew steadily during the years of the Weimar Republic. At the time of the rise of the Third Reich, principles such as the Lebensunwertes Leben (life unworthy of life) were a key part of the national eugenics ideology for purifying the Nordic population of the German people. One of the first laws passed after Hitler came to power in 1933 was the Genetic Disease Prevention Act, which required sterilization of people with schizophrenia, deafness, blindness, epilepsy, and disease. Huntington and other conditions that were considered. clearly genetic. As with tenacious but fallacious American control of inheritance, most of these conditions are not directly Mendelian, and in one case, Huntington’s, the disease takes effect after reproductive age. Sterilization had no effect on her inheritance.
The development of Nazi eugenics programs was intellectually and financially supported by American eugenicists, who were mistakenly obsessed with finding unique Mendelian genes for complex traits and tracing them into pedigrees. In 1935, a propaganda short film called Das Erbe (The Legacy) was released in Germany. In it, a young scientist observes a pair of deer beetles rolling. Confused, she consults her teacher, who makes her sit down to tell her about Darwinian struggles for life, and shows her a movie of a cat hunting a bird with roosters fighting. Suddenly he succeeds and exclaims, with a laugh, “Animals follow their own racial policies!”
Confused propaganda is clear: nature purges the weak, and so do we.
An image from the 1935 Nazi propaganda film Das Erbe, which combines natural selection and eugenics. Photo: YouTube / ORF2
The movie below shows a pedigree of a hunting dog, the type you might get from the Kennel Club today. And then there is an animation of the Kallikak family tree, Erbgesunde Frau on one side and Erbkranke Frau on the other: genetically healthy and hereditarily defective women. On the sick side, the positions of all evildoers and deviants are palpable to show the flow of undesirable people through the generations, as the voice-over explains. Das Erbe was a film to promote public acceptance of the laws of Nazi eugenics, and what follows Kallikak’s family tree, totally fictitious, is his asserted legacy: shocking images of seriously …