The Invisible History of the Human Race (7 page)

Yet as many of the nation’s people began to leave thicker and thicker trails of records, one group had to deal with the fact that all their historical information had been stolen.

Slaves had been brought to America with nothing more than their memories, and after several generations the descendants of those slaves had little chance of confidently tracing the origins of their ancestors. Once in America, however, the lives of African Americans began to be documented, including by deeds of sale; court records; birth, marriage, and other parish records; and military and census data. In contrast to the genealogical curiosity of Americans of northern European descent, it wasn’t until late in the twentieth century that African Americans began to study their heritage. A key moment was the publication of
Roots
by Alex Haley in 1976. Allegedly based on a true story, the book was an international success and ignited a passion for personal history in the communities of many minorities, as well as reviving mainstream interest in genealogy.

As it turned out, some of the material in
Roots
has since been disproved, from inaccuracies about the accounts of many characters’ lives in Africa (if not their actual existence) to the claim that all African Americans were descended only from slaves. (Just before the Civil War, one in eight black Americans was free.) Still, even if Haley’s own claim that he was America’s foremost expert on black genealogy has been challenged,
Roots
was a hugely significant book that enlivened history once more for an enormous number of people who had been shut out of it.

 • • • 

Before the twentieth century most documentation concerning heredity was either a personal aid to memory or concerned with legal matters. But in the early twentieth century genealogy became much more connected to biology. It’s hard now for us to think of the two as separable, but connecting them was a process of discovery that involved many different minds in many different fields. As scientific ideas were developed about what was passed down, how it was passed down, and what it meant about who we were, they were inevitably shaped by our historical understanding of what is passed down. Thus the initial insights of scientific genealogy reflected the attitudes of the day, like the notion that poverty, talent, and goodness were inherent and—long before anyone began to worry about genetic determinism—the idea that some groups of people were inherently superior to others.

We must, if we are to be consistent, and if we’re to have a real pedigree herd, mate the best of our men with the best of our women as often as possible, and the inferior men with the inferior women as seldom as possible, and bring up only the offspring of the best.

—Plato,
Republic

I
t started with sheep. In the mideighteenth century Robert Bakewell, a gentleman farmer from Dishley Grange, Leicestershire, had a particular talent for noticing what got passed down from a parent to its offspring, and how. For instance, Bakewell realized that specific traits were often linked with families and that the contribution of both ram and ewe had an impact on their offspring. He learned that not only could specific traits be passed down, but sometimes an entire group of traits seemed to be linked, so that the presence of one predicted another. An innocent mark on a sheep’s face, for example, might signal that it also had a much more significant trait.

Bakewell began to experimentally breed his sheep and he became skilled at selecting for different traits. Until this point farmers had mostly used an animal’s ancestry as a guide to its breeding potential. But Bakewell realized that an individual animal should be evaluated for its own particular set of traits and then methodically bred—or not bred—accordingly. Part of his genius was a knack for amplifying good traits while controlling for bad ones.

At first in secrecy and then to great public acclaim and popularity, Bakewell created a new breed of sheep. Called the Dishley sheep, it had fine bones, fattened up fast, and possessed a strange but wonderful barrel-shaped body whose most valuable parts were larger (while the parts with no market value were smaller).

For generations before Bakewell farmers had bred their sheep for valuable qualities, and with experience they began to develop practical rules for the process. Even though they did not understand that parents pass on specific traits to offspring, they had long recognized that one animal could be of more value than another and that the best animals had great currency in trade and war. The basic rule of thumb, which had been around since the time of the Greeks, was “like begets like” (still a reasonable guide today). But even though their experiences had enabled farmers to formulate reliable axioms for producing good stock, they did not create any new breeds. At the time, they didn’t conceive of the process of selection and reproduction of stock over generations as “heredity”; rather, they envisioned it as a holistic process and spoke about the way sires might “leave an impression” or
make a “stamp” on offspring.

The understanding of reproduction at the time was still heavily influenced by the Bible’s version: Humans are “fashioned to be flesh . . . , being compacted in blood, of the seed of man.” Some farmers believed that traits were passed down by blood, and some thought that particles in the blood collected in the testicles and were somehow turned into seed. The basic idea was that beings were not
reproduced
; they were
created
. Therefore an individual animal was shaped by its ancestry but also by the weather, its food, or even its dreams. The most delicate moment in the creation of an animal was the moment of its conception. Even what the mother was looking at when the animal was conceived could shape it.

For a long time farmers believed that the health of stock was so closely connected to its environment that if you moved it from place to place, it would degenerate and its value would suffer. It was thought as well that males and females made different contributions to the creation of a new being. Some theorists attributed most of the creative power to the egg (which was woken up by the sperm) or, more typically, to the sperm, which planted the stuff of life in the egg. Bakewell’s experiments made it clear that the female was as important as the male when it came to breeding.

In 1783 Bakewell founded an association to regulate the leasing of the Dishley to other farmers for breeding. It was the first time that a farmer systematically leased stock based on its breed (and charged revolutionary prices for the privilege). Bakewell’s experiments soon gave rise to a large collective activity, and the combined genius—and stock—of his neighbors and, later, of most of sheep-breeding society changed what we know about the way that traits move through generations.

Bakewell became known as the “Prince of Breeders,” and his Dishley sheep made their way throughout England and on to Europe and America, eventually being bred in Australia and New Zealand as well. By 1790 one of his contemporaries made the modern-sounding observation that Bakewell’s experiments showed that “a number of traits were found, in some considerable degree at least, to be hereditary.” That principle didn’t apply only to sheep, as Bakewell also bred cattle and horses that became extremely popular with other breeders. Before his experiments farmers spoke of characteristics that remained “constant” and true” over generations; afterward “inheritance” became accepted as a fundamental mechanism. In 1915, more than a hundred years after his death, the
Breeder’s Gazette
,
the most widely read breeding publication in the world, wrote:

Flying squarely in the face of all preconceived notions governing the production of farm animals, he was the first of the world’s great animals breeders, [demonstrating] the readiest and most effective method of establishing and fixing desired characteristics.

Bakewell’s keen powers of observation and his systematic approach forever changed the way people thought about what gets passed down—and the extent to which it can be controlled. But even though he developed masterful techniques for manipulating heredity, he didn’t understand its mechanics. That would take another century.

 • • • 

After sheep breeders, the second-most-important group in the history of heredity was the French medical community. Before the early nineteenth century
hérédité
was primarily a legal term used with reference to inheritance and bloodlines, but around 1830 French doctors began to think about the hereditary transmission of physical features through families and to use the word in a biological context. After 1840 doctors also considered the possibility of moral or
psychological traits being passed down.

By the end of the nineteenth century, doctors—and increasingly other scientists in the life sciences—came to agree that heredity might explain a whole set of phenomena that had previously been thought to be entirely unrelated, like the recurrence of disease and resemblance in families, the differences among races, and even the formation of species. It was possible for the first time to talk about traits and the connections between them without also speaking of the specific individuals who possessed those traits.

At around the same time, Gregor Mendel became the first person to figure out how this process actually worked, or at least how part of it worked. Born in 1822 in northern Moravia (now in the Czech Republic), Mendel grew up toiling in his family’s orchards. In 1843 he entered the monastery of St. Thomas in Brno and began to work for Abbot Cyril Napp, who was head of the Moravian Agricultural Society, as well as a member of a number of other agricultural and scientific societies. Napp sent Mendel to study at the University of Vienna for two years. On his return Mendel was asked to look after the monastery’s garden, where he began a series of studies of pea plants, investigating the transmission of characteristics between generations, applying pollen to the plants himself with a small paintbrush.

Mendel experimented with height, color, seed texture, and other features, and he concluded that for certain traits offspring received something from each parent that contributed to the trait. The elements that were passed down were either dominant or recessive, meaning that if one parent passed on a dominant version of a trait (like smooth skin) and the other parent passed on a recessive version (like wrinkled skin), then the dominant would always appear in the offspring. If both parents passed on the dominant trait, then that would also appear in the offspring. Only if both parents passed on the recessive trait would that characteristic emerge in the offspring. If parents with a dominant and recessive element had four offspring, the probability was that three would have the dominant trait and only one would have the recessive.

Mendel’s theory explained how children may possess a trait that is the same as one parent’s but not the other, and why some traits seem to skip a generation. If an individual received the dominant element from one parent and the recessive element from the other, he will express the dominant element, but he might pass the recessive version on to his own offspring. If that offspring also received a recessive element from its other parent, then it might look more like one of its grandparents than either parent.

Mendel published a paper about his findings in 1866, but it had little impact; he, much like Bakewell, was so ahead of the preconceived notions of the day that the significance of his insights was not appreciated. It wasn’t until three decades later that scientists came to realize that Mendel had neatly outlined some of the key principles of heredity. In 1906 the English scientist William Bateson first used the term “genetics” to describe work based on those principles.

For all the individual contributions, collaboration, experimentation, and inspiration that it took to develop the idea of heredity, it was only the first idea of three that would radically change the way people thought about generations and genealogy in the late nineteenth century. The second idea was, of course, evolution.

 • • • 

It’s hard to overstate the impact that the concept of evolution has had on all science, medicine, conservation, and social sciences and on most of modern-day life. When Darwin’s
On the Origin of Species
was published in 1859, its definitive dismissal of a divine creation caused a furor. Darwin proposed that the individuals within a species naturally varied from one another. They adapted to their environment, and the animals that were best adapted reproduced in greater numbers. Darwin’s theory made it possible for science to think beyond the genealogy of the human race and imagine an unbroken line of mothers, beginning at one end with a creature that looked like a chimpanzee and continuing down through the line—each mother giving birth to and caring deeply for her child—to stop at the other end with us. Still, while Darwin knew that something
like
genes must be at work in the creation of individuals and species,
he didn’t know what that actual material was.

Darwin was influenced by the French discussion of
hérédité
, and he later even offered his own theory of hereditary transmission, which he called pangenesis. He proposed that small particles, called gemmules, were passed from parent to offspring and that they accumulated and helped shape traits. Although it was a flawed theory and was never seriously taken up, Darwin understood that heredity needed to explain how traits that weren’t apparent in a parent might appear in a child. Sadly, he never became aware of Mendel and his experiments.

When Mendel’s discovery was finally taken up, it was with great and universal enthusiasm, because it so eloquently explained an observable phenomenon and helped breeders make reliable predictions. It also appealed because of its neat calculus, one that made something that had once been so mysterious now seem so controllable. The intoxicating feeling of mastery, plus the grand vision that evolution provided, seemed to lead to the tantalizing conclusion that men should take charge of the process. If artificial selection could be used to create better cattle, horses, and sheep, then why not create better humans as well? Eugenics was the third idea to completely transform how we conceive of generations and what is passed between them.

Francis Galton, Charles Darwin’s first cousin, thought that breeding better humans was an excellent idea, and thus the science of eugenics, a term that Galton coined, was born as a twin to the science of heredity. Galton enthusiastically conducted wide-ranging inquiries into heredity and many other fields. Like many other scientists at the time he was able to fund his own experiments through his family’s wealth, and he ranged far and wide geographically as well as intellectually. Galton became a rather famous explorer of South Africa and an influential early student of meteorology, and he worked out a method of categorization of fingerprints that is still used today. He was also the first person to study heredity in twins and develop a formula for predicting how much of a trait is inherited.

Galton was profoundly influenced by Darwin’s ideas, as well as by his success. To test the notion that gemmules circulated in blood, Galton transfused blood between unrelated rabbits to see if traits could be passed on that way, an experiment that proved unsuccessful.

Still, Galton was enthusiastic about the idea that artificial selection—that is to say, breeding—could weed out bad qualities and foster good ones in humans. Indeed, he believed that many traits were heritable in a straightforward way. If your father was brilliant, you had a good chance of being brilliant. If your father had a weak constitution and was fragile, then you probably would be too. If your parents were unsuccessful, then you would almost certainly be as well. Galton—who coined the phrase “nature and nurture”—also believed that biological traits were fixed, determinants of an inescapable fate that could only marginally be influenced by education or other social forces. To prove his theory, Galton assembled a list of twenty-five hundred eminent men and tracked family relationships on that list. He found that men on the list were related to each far more often than could have occurred by chance. Galton’s interpretation was that genius underlay this eminence, and that his list proved genius was heritable

The basic spirit of eugenics, then, involved grafting the ideas of breeds, traits, and improvement onto preexisting social divisions. In Galton’s Victorian world those divisions were thought to be natural, and it therefore made sense to him to look for biological rather than social explanations for the inequity in people’s lives. When conditions like poverty, criminality, and insanity were considered to be “natural,” it made sense to try to deal with them on the biological front. Why not breed them out? “What nature does blindly, slowly, and ruthlessly, man may do providently, quickly, and kindly,” wrote Galton, who believed that
eugenics could be a new religion.