In the age of selfies and social media, it seems that everyone is obsessed with discovering and projecting a certain image of themselves to the world. It could be cultivating a huge following with a clever persona on Twitter, gaining a reputation as a photogenic traveler on Instagram, searching for meaning in your Horoscope or Myers-Briggs personality test, or even mapping out your ancestry by getting your DNA tested through a genetic testing company like 23andMe. This seems to be the era of self-discovery and identity—but astrological signs and quirky, emoji-filled ‘About Me’ pages only scratch the surface of who we truly are. The question of who you are can be answered best by examining the epic tale of your unique genome. Your genome, your genes, tell the story of you, your ancestors, and all of humankind. Who are our ancestors? Where did they come from? Geneticists have suddenly become historians, and the hard evidence in our DNA has blown the lid off whatwe thought we knew. In A Brief History of Everyone Who Ever Lived, acclaimed science writer Adam Rutherford explains exactly how genomics is completely rewriting the human story—from 100,000 years ago to the present.
And it’s received some wonderful attention in the news! The book receives a rave review in this weekend’s New York Times Book Review, who calls it “nothing less than a tour de force—a heady amalgam of science, history, a little bit of anthropology and plenty of nuanced, captivating storytelling.” The book is also on Amazon’s curated list Top 100 Best Books of the Year, as well as an Editors’ pick for Best Book of the Year in both the Science and History categories. The Wall Street Journal called author Adam Rutherford “an enthusiastic guide and a good story-teller,” while Shelf Awareness for Readers said he “manages to reveal fresh (and controversial) assessments of human history and dispel long-held beliefs with clarity, enthusiasm and humor.” Rutherford was featured in interviews with National Geographic and NPR’s 1A, and his original essay on genetic and race was published to Salon.com. Excerpts and reviews of A Brief History of Everyone Who Ever Lived have also appeared in Business Insider, Pharyngula, The Atlantic, and Scientific American. This Friday, November 17th, Adam will appear on PRI’s Innovation Hub! You can tune in here: https://www.pri.org/programs/innovation-hub.
Without further ado, read on for the introduction from Adam Rutherford’s groundbreaking book, A Brief History of Everyone Who Ever Lived, excerpted below.
“In the distant future I see open fields for far more important researches . . . Light will be thrown on the origin of man and his history.”
“Chapter 14: Recapitulation and Conclusion” in On the Origin of Species by Charles Darwin, 1859
This is a story about you. It concerns the tale of who you are and how you came to be. It is your individual story, because the journey of life that alights at your existence is unique, as it is for every person who has ever drawn breath. And it’s also our collective story, because as an ambassador for the whole of our species, you are both typical and exceptional. Despite our differences, all humans are remarkably close relatives, and our family tree is pollarded, and tortuous, and not in the slightest bit like a tree. But we are the fruit thereof.
Something on the order of 107 billion modern humans have existed, though this number depends on when exactly you start counting. All of them—of us—are close cousins, because our species has a single African origin. We don’t quite have the language to describe what that really means. It doesn’t, for example, mean a single couple, a hypothetical Adam and Eve. We think of families and pedigrees and genealogies and ancestry, and we try to think of the deep past in the same way. Who were my ancestors? You might have a simple, traditional family structure or, one like mine, handsomely untidy, its tendrils jumbled like old wires in a drawer. But no matter which, everyone’s past becomes muddled sooner or later.
We all have two parents, and they had two parents, and all of them had two parents, and so on. Keep going like this all the way back to the last time England was invaded, and you’ll see that doubling each generation results in more people than have ever lived, by many billions. The truth is that our pedigrees fold in on them- selves, the branches loop back and become nets, and all of us who have ever lived have done so enmeshed in a web of ancestry. We only have to go back a few dozen centuries to see that most of the 7 billion of us alive today are descended from a tiny handful of people, the population of a village.
History is the stuff that we have recorded. For thousands of years, we have painted, carved, written, and spoken the stories of our pasts and presents, in attempts to understand who we are and how we came to be. By consensus, history begins with writing. Before that we have prehistory—the stuff that happened before we wrote it down. For the sake of perspective, life has existed on Earth for about 3.9 billion years. The species Homo sapiens, of which you are a member, emerged a mere 300,000 years ago, as far as we know, in pockets in the east and north of Africa. Writing began about 6,000 years ago, in Mesopotamia, somewhere in what we now call the Middle East.
For comparison, the book you are holding is around 115,000 words, or 685,000 characters long, including spaces. If the length of time life has existed on Earth were represented as this book, each character, including spaces, is around 5,957 years. Anatomically modern humans’ tenure on Earth is equivalent to
. . . the precise length of this phrase.
The time we have been recording history is an evolutionary wingflap equivalent to a single character, the width of this period<.>
And how sparse that history is! Documents vanish, dissolve, decompose. They are washed away by the weather, or consumed by insects and bacteria, or destroyed, hidden, obfuscated, or revised.
That is before we address the subjectivity of the historical record. We can’t agree definitively on what happened in the last decade. Newspapers record stories with biases firmly in place. Cameras record images curated by people and only see what passes through the lens, frequently without context. Humans themselves are terribly unreliable witnesses to objective reality. We fumble.
The precise details of the events of September 11, 2001, when the World Trade Center towers were destroyed, may well remain obscure because of conflicting reports and the chaos of those horrors. Witness testimonies in courts are notoriously defective and are always subject to squint-eye scrutiny. Flit back a few centuries, and there is no contemporary evidence even for the existence of Jesus Christ, arguably the most influential man in history. Most of our tales about his life were written in the decades after his death by people who had never met him. Today, we would seriously question that, if it were presented as historical evidence. Even the accounts that Christians rely on, the Gospels, are inconsistent and have irreversibly mutated over time.
This is not to disparage the study of history (nor Christianity). It’s merely a comment on how the past is foggy. Until recently it was recorded primarily in religious texts, business transaction documents, and the papers of royal lineages. In modern times we have the opposite problem—far too much information and almost no way to curate it. In every purchase you make online, every Internet search you do, you volunteer information about yourself to be captured by companies in the ether. Books, sagas, oral histories, inscriptions, archaeology, the Internet, databases, lm, radio, hard drives, tape. We piece together these bits and bytes of information to reconstruct the past. And now, biology has become part of that formidable swill of information.
The epigraph at the beginning of this introduction is Darwin’s single reference to humans in On the Origin of Species, right at the end, as if to tease us that there will be a sequel. With his proposed theory of descent with modification in the distant future, light will be shed on our own story: to be continued.
That time has come. There is now another way to read our pasts, and floodlights are being shone on our origins. You carry an epic poem in your cells. It’s an incomparable, sprawling, unique, meandering saga. About a decade ago, fifty years after the discovery of the double helix, our ability to read DNA had improved to the degree that it was transformed into a historical source, a text to pore over. Our genomes, genes, and DNA house a record of the journey that life on Earth has taken—4 billion years of error and trial that resulted in you. Your genome is the totality of your DNA, 3 billion letters of it, and due to the way it comes together—by the mysterious (from a biological point of view) business of sex—it is unique to you. Not only is this genetic fingerprint yours alone, it’s unlike any other of the 107 billion people who have ever lived. That applies even if you are an identical twin, whose genomes begin their existence indistinguishable, but inch away from each other moments after conception. In the words of Dr. Seuss:
Today you are you! That is truer than true! There is no one alive who is you-er than you!
The sperm that made you started its life in your father’s testicles within a few days before your conception. One single sperm out of a spurt of billions ground its head against your mother’s egg, one of just a few hundred. Like a Russian doll, that egg had grown in her when she was growing inside her mother, but it matured within the last menstrual cycle and, taking its turn from alternating ovaries, eased its way out of the comfort of its birthplace. On contact, that winning sperm released a chemical that dissolved the egg’s reluctant membrane, left its whiplash tail behind, and burrowed in.
Once inside, the egg set an impenetrable fence that stopped any others breaching her defenses. The sperm was unique, as was the egg, and the combination of the two, well, that was unique too, and that became you. Even the point of entry was unique. Your mother’s egg being roughly spherical, that sperm could’ve punched its way in anywhere, and at the behest of cosmic happenstance, it penetrated its quarry at a singular point, a point that set waves of chemicals and effectively began the process of setting your body plan—head at one end, tail at the other. In other organisms, we know that if the winning sperm had come in on the other side, the embryo that became you would’ve started growing in a different orientation, and it may well be the same in us.
Your parents’ genetic material, their genome, had been shuffled in the formation of sperm and egg, and halved. Their parents, your grandparents, had provided them with two sets of chromosomes, and the shuffle mixed them up to produce a deck that had never existed before, and never will again. They also bestowed upon you just a bit of unshuffled DNA. If you’re a man, you have a Y chromo- some that was largely unchanged from your father and from his father and so on back through time. It’s a stunted shriveled piece of DNA, with only a few genes on it and a lot of debris. The egg also had some small loops of DNA hiding inside, in its mitochondria, tiny powerhouses that provide power for all cells. It has its own mini genome, and because it sits inside the egg, this only comes from mothers. Together, these two make up a tiny proportion of your total DNA, but their clear lineages have some use when tracking back through genealogies and ancient history. However, the vast majority of your DNA was forged in the shuffle of your parents’, and theirs in theirs. That process happened every time a human lived; the chain that precedes you is unbroken.
They fuck you up, your mum and dad.
They may not mean to, but they do.
They fill you with the faults they had
And add some extra, just for you.
I offer no comment on the psychological or parental aspects of Philip Larkin’s poem, but from a biological point of view, it’s spot on. Each time an egg or sperm is made, the shuffle produces new variation, unique differences in the people that host them. You’ll inherit your parents’ DNA in unique combinations, and in that process—meiosis—you also will have invented some brand new genetic variations, just for you. Some of those will get passed on if you have children, and they will acquire their own as well.
It’s upon these differences in populations that evolution can act, and it’s in these differences that we can follow the path of human- kind, as we have roamed across land and oceans, and oceans of time, into every corner of the planet. Geneticists have suddenly become historians.
A single genome contains a huge amount of uncurated data, enough to lay out plans for a human. But genomics is a comparative science. Two sets of DNA from different people contain much more than double that information. All human genomes host the same genes, but they all may be slightly different, which accounts for the fact that we are all incredibly similar, and utterly unique. By comparing those differences we can make inferences about how closely related those two people are, and when those differences evolved. We can now extend these comparisons to all humanity, as long as we can pull DNA from your cells.
When the first complete human genome was published in 2001 to great fanfare, it was in fact a sketchy draft readout of most of the genetic material of just a few of us. To get this far had taken hundreds of scientists the best part of a decade, and had cost on the order of $3 billion, approximately $1 per letter of DNA. Just fifteen years later, things are emphatically easier, and the amount of data from individual genomes now is incalculable. As I write these words we have approximately 150,000 fully sequenced human genomes, and useful samplings from literally millions of people, from all over the world. Grand medical endeavors with accurate names like “The Hundred Thousand Genome Project” typify how easily we can now extract the data that we all store in our living cells. Here in the UK, we are seriously considering sequencing genomes of everyone at birth. And it’s not limited to the rigor of formal science or govern- mental medical policy: You can spit in a test tube and get a read-out of key parts of your own genome from an armada of companies that will tell you all sorts of things about your characteristics, history, and risk of some diseases, for just a couple of hundred dollars.
We now have genomes of hundreds of long dead people too to slot into this grand narrative. The bones of an English king, Richard III, were identified in 2014 with a raft of archaeological evidence (Chapter 4), but the deal was royally sealed with his DNA. The kings and queens of the past are known to us because of their status, and because history is dominated by telling and retelling their stories. While genetics has enriched the study of monarchs, DNA is the ultimate leveler, and our newfound ability to extract the nest details of the living past has rendered this an examination of the people, of countries, of migration, of everyone. We can test, and verify or falsify, and know the histories of the people, not just the powerful or the celebrities of their day. Nobodies from the past are being elevated to some of the most important people who ever lived. DNA is universal and, as we’ll find out, being in a royal lineage might afford you divine rights over citizens, and the spoils that go with inherited power, but evolution, genetics, and sex are largely indifferent to nationalities, borders, and all that heady power.
And we can look further still. The study of ancient humans was once limited to old teeth and bones and the ghostly traces of their lives left in dirt, but we can now piece together the genetic information of truly ancient humans, of Neanderthals and other extinct members of our extended family, and these people are revealing a new route to where we are today. We can pluck out their DNA to tell us things that could not be known in any other way—we can, for example, know how a Neanderthal person experienced smell.
Retrieved after epochs, DNA has profoundly revised our evolutionary story. The past may be a foreign country, but the maps were inside us the whole time.
The amount of data this new science is generating is colossal, phenomenal, overwhelming. Studies are being published every week that upend what has come before. In the penultimate stages of writing this book, the date of the great exodus from Africa may have shifted more than 10,000 years earlier than previously thought, following the discovery of forty-seven modern teeth in China. Then in the final stages it moved back by another 20,000 years with the detection of Homo sapiens DNA in a millennia-dead Neanderthal girl. These numbers are not much in evolutionary terms, ripples in geological time. But that is much more than the whole of written human history, and so the land continually and dramatically moves under our feet.
The first half of this book is about the rewriting of the past using genetics, from a time when there were at least four human species on Earth right up to the kings of Europe into the eighteenth century. The second half is about who we are today, and what the study of DNA in the twenty-first century says about families, health, psychology, race, and the fate of us. Both parts are drawn from using DNA as a text to sit alongside the historical sources we have relied on for centuries: archaeology, rocks, old bones, legends, chronicles, and family histories.
Although the study of ancestors and inheritance is as old as humans, genetics is a scientific field that is young, with a difficult short history. Human genetics was born as a means of measuring people, comparatively, such that the differences between them could be formalized as science, and used to justify segregation and subjugation. The birth of genetics is synonymous with the birth of eugenics, though at the time in the late nineteenth century, that word did not carry the same toxic meaning that it has now. There is no more controversial subject in all of science than race—people are different from each other, and the weight of those differences is something that has caused some of the deepest divisions and cruelest, bloodiest acts in history. As we will see, modern genetics has shown how we continue to get the whole concept of race so spectacularly wrong. Humans love telling stories. We’re a species that craves narrative, and more specifically, narrative satisfaction— explanation, a way of making sense of things, and the ineffable complexities of being human—beginnings, middles, and ends. When we started to read the genome, what we wanted to find there were narratives that tidied up the mysteries of history and culture and individual identity, that told us exactly who we were, and why.
Our wishes were not satisfied. The human genome turned out to be far more interesting and complicated than anyone anticipated, including all the geneticists who remain ever more gainfully employed a decade on from the so-called completion of the Human Genome Project. The truth of this complexity and our lack of understanding is struggling to filter down into what we talk about when we talk about genetics. We once spoke of blood and blood- lines as a means of tying us to our ancestors and describing our familial selves. It’s no longer in the blood, it is in our genes. DNA has become a byword for destiny, or a seam running through us that seals our fates. But it is not. All scientists think that their field is the one that is least well represented in the media, but I’m a scientist and a writer, and I believe that human genetics stands out above all as one destined to be misunderstood, I think because we are culturally programmed to misunderstand it.
Science is apt to reveal that much of the world is not how we perceive it, whether that is the cosmological, the molecular, the atomic, or the subatomic. These fields are distant or abstract com- pared with how we talk about families, about inheritance, about race, about intelligence, and about history. The baggage we carry, the subjectivity with which we naturally approach these quintessentially human characteristics is without equal. The gap between what science has revealed and how we talk about families and race is a chasm, because, as we shall see, things are not how we thought they were.
There’s plenty of fabrication and mythmaking born of DNA as well. Genetics can certainly tell us who our closest relatives really are, and can reveal so many mysteries of our deep past. But you have far less in common with your ancestors than you may realize, and there are people in your family from whom you have inherited no genes at all, and who therefore have no meaningful genetic link to you, even though in a genealogical sense you are most definitely descended from them. I will show you that despite what you might have read, genetics won’t tell you how smart your kids will be, or what sports they should play, or what gender person they might fancy, or how they will die, or why some people commit acts of heinous violence and murder. Just as important as what genetics can tell us is what it can’t.
Our DNA is the very thing that has encoded brains sophisticated enough to be capable of asking questions about our own origins, and providing the tools to figure out how our evolution has proceeded. Changes in this strange molecule have accumulated and been recorded over time, waiting patiently for millennia for us to dis- cover how to read it. And now we can. Each chapter in this book tells a different story about history and about genetics, of battles lost and won, of invaders, marauders, murder, migration, agriculture, disease, kings and queens, plague, and plenty of deviant sex.
Above all, you are holding a history book. Some of the stories here are the history of genetics—with all its own convoluted twists and dark past—included to understand how we know what we now are discovering. Many of the stories are tales of nations, populations, a few known through celebrity or inheritance of power, but most are of the anonymous multitudes. We can pick through the bones of individual men, women, and children who through sheer chance died in uncommon circumstances, and turned out to be the people whose lives we would scrutinize forensically because in the preservation of their death they inadvertently gave up their DNA to us.
Biology is the study of what lives and therefore what dies. It’s messy—wonderfully, frustratingly so—and imprecise and defies definitions. If you want to start at the beginning, which might seem like a very good place to start, then here is where our troubles begin.
For more of Adam Rutherford’s intriguing findings and hilarious commentary, check out A Brief History of Everyone Who Ever Lived, available here and wherever else books are sold.