The Invisible History of the Human Race: How DNA and History Shape Our Identities and Our Futures

Africans believed they were being captured and shipped over the ocean to be eaten. The insecurity of life in a world of slavery is hard to imagine, let alone the extraordinary length of time that the threat of abduction loomed.

After a few minutes, though, I started to take in what all the attendees were looking at: hundreds and hundreds of historical documents, self-published books, CD-ROMs with lists of lists of names, databases chock-full of people who had once lived and whom no living person now remembered. Everyone in this hall was looking for someone who was gone forever.

Although Winkler had always known that his family had Native American and white ancestry, this new affiliation was a complete surprise. “I had always assumed that my dad’s family was mostly Indian, because that’s what they looked like and that’s what they always said,” Winkler recalled. When he eventually asked his father why he had always described himself as being an Indian, his father replied, “Everybody knows what an Indian is. It takes all day to explain what a Melungeon is.

As a graduate student Nathan Nunn, now a Harvard economist, began to compare different economies in modern Africa, and he found that the countries that lost more people to the slave trade were also the poorest countries today. How

As of 2014 a small handful of well-known companies—Family Tree DNA, 23andMe, and, as well as National Geographic’s Genographic Project—and services offer a selection of DNA tests and genealogical connections to the general public.

Because Y DNA and mtDNA don’t get reshuffled with other DNA, they can be used to learn something about an individual in your family tree who lived 10,000, 50,000, or 100,000 years ago. That person is still there, in a sense, in you in a completely disproportionate way to the rest of your grandparents.

Despite the availability of testing, at least half of the population at risk for Huntington’s disease still has children without making use of the new technologies. Even some of the people who have prenatal testing for Huntington’s still have a profound reluctance to learn their own status. Couples who try preimplantation genetic diagnosis may even conceive a child and choose not to find out if the parent at risk has the mutation. Deciding

genealogy companies have quietly and steadily expanded to become some of the biggest data organizations of the twenty-first century.

Here is where it becomes clear that this kind of fine-grained genetic history is the flip side of the family-history coin. Although genealogy is not widely valued in academia, it meshes perfectly with, and helps explain, social history. These small stories about individual lives reveal the way that individual choices shape the biology and the history of whole populations.

If the hyperconnectedness of humanity is true, it would mean that everyone alive today—you, your neighbor, Vladimir Putin, and the emperor of Japan—could count the same Egyptian pharaoh, as well as everyone else alive at the time, as a distant grandparent.

If you built a time machine and traveled back four hundred years and, let’s say for the sake of argument, found yourself in a romance with one of your sixteenth-grade grandmothers, the good news is that you can feel fine about having children together. However morally bizarre that might be, it would not be genetically problematic.

In one of the most remarkable studies of the transmission of ideas over time, the economists Nico Voigtländer and Hans-Joachim Voth found evidence that animosity endured generation after generation, for as long as six hundred years. Voigtländer

In the course of evolution humans have also lost huge numbers of working genes along with the abilities and traits they generated. In recent years scientists announced that human bitter-taste-receptor genes are losing their function. Identifying bitterness helps animals avoid toxic foods, precisely because so many of them taste bitter. For humans, however, an increase in meat consumption and a decrease in plant food, as well as the use of fire, which renders many toxins harmless, have meant that these bitter-taste-receptor genes are no longer maintained by natural selection. As a result they have effectively become useless.

It is extremely unlikely that anyone in the twenty-first century does not have some consanguinity in his or her family within the last three hundred years. Yet according to Feldman, more than half of all human populations today still engage in consanguineous marriage, and up to 10 percent of all humans are in first- or second-cousin marriages.

It is well known that onset of the disease is affected by lifestyle, yet even when the at-risk subjects were given information about their susceptibility, many did not adjust their fat intake or increase exercise or consult medical specialists to minimize their risk.

Most curious is the way that Y/surname patterns differ between countries. In Britain, on average, a man who has the same surname as another is significantly more likely to have a similar Y chromosome, and therefore a common ancestor, than he would with someone of a different surname. But there’s a twist: The Y similarity depends on the frequency of the surname within the population. If you are a Smith, for example, the rule does not apply.

not put in place, one wonders how insurance and pharmaceutical companies will treat our grandchildren if they have genetic information about them, perhaps even before they are even conceived. Insurance

One cannot and must not try to erase the past merely because it does not fit the present. —Golda Meir

Remember Essie Mae Washington-Williams, the illegitimate daughter of Senator Strom Thurmond? She said, “There are many stories like Sally Hemings and mine. [Hemings, a slave, had children fathered by the United States president Thomas Jefferson. See chapter 11.] The unfortunate measure is that not everyone knows about these stories that helped to make America what it is today.” What America is today is a nation where the Supreme Court has ruled that all states must allow same-sex marriage.

Some parts of the genome with a high frequency of Neanderthal variants shape hair and skin color and likely made the first Eurasians lighter-skinned than their African ancestors.

Study the past if you would define the future. —Confucius O

Surnames have the longest history in China, where they began around five thousand years ago. They are about seven hundred years old in England, where they became hereditary in the fifteenth century (and likely earlier). They became hereditary in Scotland a century after that. Surnames are older in Ireland, beginning around nine hundred years ago. In the Netherlands they’ve only been in use for the last two hundred years. In Turkey they were adopted in the early twentieth century. Iceland is the only European country to retain the older-style patronymic that many other countries abandoned, in which children are surnamed with the father’s forename appended to the word for “son” or “daughter,” so the surname changes every generation.

The history of the world may be writ in your cells, all of it personal to your lineage and some of it part of the broader context, but though you have been shaped by history, you have only been shaped by some of it. Fundamentally,

The McEvoys, for their part, apparently had two dominant founding Y chromosomes, a theory that is supported by records revealing that when the name was anglicized, two ancient families, the Mac Fhiodhbhuidhes and the Mac an Bheathas, were drawn in under the same banner and both became McEvoys. History also indicates that fully three Irish surnames—McGuiness, Neeson, and McCreesh—are all anglicizations of the same Gaelic name Mac Aonghusa (son of Angus), which DNA evidence confirms, as all three groups overlap strongly on one Y.

The nineteenth-century German missionary Sigismund Koelle asked over 140 ex-slaves how they had been taken. Almost 20 percent of them told him that family or friends had given them up.

The problem of rapidly evolving technologies or “digital migration” was rather alarmingly illustrated in England in the 1980s with a considerably larger amount of information. Actually, it began in 1086 with the Domesday Book. The first public record ever made in England, the Domesday Book was instigated by William the Conqueror, who wished to take a census of his people and, more specifically, their possessions.

This is because our personal genetic tree is not equivalent to our genealogical tree, which is to say that not every one of our direct ancestors has contributed to our genome.

Totalitarian power thrives when it alienates people from basic information about themselves. When European slavers abducted people from Africa, they essentially took away their history as well.

Where genealogy was concerned, I met many people who proclaimed their indifference to it, but it was often an extremely vigorous indifference.

You may discover that a certain sequence of letters in your autosomal DNA is typically found in someone with Finnish heritage or Korean ancestry. Only a few years ago the world of science was turned upside down when it was discovered that in ancient times two nonhuman species contributed to the human genome.