A Brief History of Everyone Who Ever Lived: The Human Story Retold Through Our Genes
Kindle Highlights
Plus ça change, plus c’est la même chose.
DNA says that caste predates colonial India by centuries.
Ignorance more frequently begets confidence than does knowledge
“Yet man is born unto trouble, as the sparks fly upward.” Job 5:7
Which just goes to show that the very best geniuses can also be idiots.
These, it cannot be stated enough, are calculations of odds, not of destiny.
The past may be a foreign country, but the maps were inside us the whole time.
No single technique was ever going to explain a human, and that quest is endless.
What a senseless phrase is “curiosity killed the cat.” To be incurious is to be inhuman.
we can, for example, know how a Neanderthal person experienced smell. Retrieved after epochs,
Mark Twain wrote in 1869 that “travel is fatal to prejudice, bigotry, and narrow-mindedness.”
You carry an epic poem in your cells. It’s an incomparable, sprawling, unique, meandering saga.
human variation is pretty continuous. The concept of a discrete or pure race vanishes in the haze.
Typical general anesthetics are a cocktail of drugs that do specific things to beckon the sandman.
There’s no such thing as a Jewish disease, because Jews are not a genetically distinct group of people.
Long gone are the days when Victorian gentlemen could idle away their inheritances in hot pursuit of the fabric of nature.
epicanthic fold, which gives them an eye shape unlike others, and is largely absent in the people of the rest of the world.
The analogy does though satisfy the question of how many races there are: It is unanswerable. It is a meaningless question.
Something on the order of 107 billion modern humans have existed, though this number depends on when exactly you start counting.
DNA is a coded alphabet to be translated by the mechanics of a living cell into a protein; all life is made of, or by, proteins.
For one so formal in measurement and in categorization, Galton shows his racist hand in being so relaxed about these definitions.
It’s an incredibly clever way of reading DNA, and Fred Sanger quite rightly picked up his second Nobel Prize for Chemistry* for inventing it.
The genome is a history book, and we will not cease from exploring it, and as long as there are people our exploring will never be at an end.
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.
Around a million years ago, somewhere in Africa, a group of humans lived who were to be separated into us, the Neanderthals, and the Denisovans.
If you’re broadly eastern Asian, you’re almost certain to have Genghis Kahn sitting atop your tree somewhere in the same manner, as is often claimed.
The mix of history, archaeology, and now DNA is building a new picture not just of migration, but of the evolution of us—how we came to be what we are.
For the time being, though, let us think of species as distinct groups of animals, who are different enough to be incapable of producing fertile offspring together,
There are no essential genetic elements for any particular group of people who might be identified as a “race.” As far as genetics is concerned, race does not exist.
Red hair appearing exclusively in beards is not uncommon, though we don’t really know why. Forgive us; it’s not really been a research priority over the last few decades.
The question of race is explored in depth in Chapter 5, and I will explain why geneticists ascribe no scientific value to these broad racial attempts at definitions of peoples.
It is not possible to predict the complex behaviors of someone solely by the bumps and bulges and basic morphology of the skull. And it’s not possible to do it with DNA either.
He went further, into what is now Namibia, on a two-year trip with the Royal Geographical Society, and published bestsellers describing his journeys into the heart of darkness.
The indigenous people hadn’t always been there, nor had they originated there, as some of their traditions state, but they had occupied these American lands for at least 20,000 years.
However, the number of diseases that have been eradicated as a result of our knowing the genome? Zero. The number of diseases that have been cured as a result of gene therapy? Zero. That
Genetics has shown that people are different, and these differences cluster according to geography and culture, but never in a way that aligns with the traditional concepts of human races.
The observation that there is less Neanderthal DNA on our Xs implies that the first encounters we had with them that resulted in procreation were male Neanderthals with female Homo sapiens.
From an evolutionary point of view, perfection is boring and impractical, and infidelity is essential, at least when it comes to the code. The process of DNA replication has to be imperfect.
The seven billion of us alive today are, according to all the evidence available to us, the last remaining group of human great apes from a set of at least four that existed 50,000 years ago.
We know that the emergence of the pale skin we associate with Europe, and particularly northern Europe, only emerged in the last few thousand years, just as the genes for processing milk did.
It’s exciting to discover circus performers in one’s family tree, but I must be very careful not to fall into the trap I am decrying throughout this book, that DNA has some power to determine identity.
With that comes economic disparity: Some have surplus, others have less, which means some families get bigger, and have more children who live, more culture, more technology; and the cycle continues. By
Autism is more correctly now termed autism spectrum disorder, as there is a continuous suite of characteristics that people with autism display. Some are more severe than others; some are merely different.
Genes do not determine the outcome of almost all human biology and psychology. Dozens or hundreds of genes can be involved, each with small cumulative effects, and all mitigated by the world in which we live.
Within these samples we see more male European DNA and female African, measured by Y chromosome and mitochondrial DNA, suggesting male Europeans had sex with female slaves. Genetics makes no comment on the nature of these relations.
“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
Though most people on Earth produce eumelanin, which is brown or black, in people for whom their MC1R contains a redhead mutation, phaeomelanin is produced. The melanosomes feed into the base of a hair follicle and this is what makes redheads redheads.
Black, as discussed above, is virtually meaningless as a scientific descriptor, and Africa as a racial group is also of very limited use because black people are more likely to be more genetically different from each other than they are from white people.
Many mammals have only two cone opsins, and so see color with less acuity than us. Most apes have three, as do the Old World monkeys that are indigenous to Africa and Asia. Cats have many more rods and so see in the dark much better than us, but not color.
It’s important to remember that the commercial DNA ancestry tests don’t necessarily show your geographical origins in the past. They show with whom you have common ancestry today. I have a few chunks of DNA that 23andMe showed are most common in Scandinavia now.
(Indeed, we did not know that DNA was the carrier of genetic information until the 1950s. The elegant double-helix structure of the most beautiful molecule in biology was solved just sixty-four years ago, and the genetic code was only deciphered in the early ’60s.)
Coexistence in Europe probably lasted around 5,000 years, which is in evolutionary measure a click of the fingers, but is a time long enough for maybe 200 generations, epic migration, cultural development, plenty of sex and death, and the general business of living.
From 1907, when Indiana passed the first mandate, until 1963, forced sterilization was legally administered in thirty-one states, with California the most vigorous adopter. The most recent cases of forced sterilization in that famously liberal state occurred in 2010.
You are of royal descent, because everyone is. You are of Viking descent, because everyone is. You are of Saracen, Roman, Goth, Hun, Jewish descent, because, well, you get the idea. All Europeans are descended from exactly the same people, and not that long ago. Everyone
According to the basic principles of forensic psychiatry, only the actual mental ability (phenotype) of the offender matters when punishment or legal responsibility is considered, and putative risk factors per se (such as genotype) have no legal role in the resulting judgment.
Galton gave us the phrase nature versus nurture, but we know now that these are not in conflict. The complex interplay between nature—that is, genes—and nurture—that is, everything apart from genes—is how a person is built. Nature via nurture is a much better way of phrasing it.
It’s not that there aren’t measurable, quantifiable differences between all these categories we impose upon things, it’s just that for the most part they fit not into discrete units, but into a continuum. We are naturally plagued by the tyranny of a discontinuous mind, as Richard Dawkins so eloquently said.
they build knowledge on the shoulders of historical and contemporary giants, as Isaac Newton once suggested, parroting the words of the eleventh-century philosopher Bernard of Chartres, who was referencing the Greek myth of the temporarily blinded hunter Orion, who saw further by sitting a dwarf on his shoulders.
We estimate based on the number and density of connections between the neurons in our skulls that the brains you and I are using right now are the most complex objects in the known universe. Yet the code that underwrites that spectacular lump of gray meat is basically the same as animals that can do none of this.
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.
We all have an enzyme called lactase, encoded by a gene called LCT, and its sole job is to digest milk. The sweetness in milk comes from a sugar called lactose, and lactase seeps out of your stomach lining and slices lactose in half to produce the sugars glucose and galactose. Elegant names are not always a preoccupation of biologists.
Audrey Hepburn was fifteen at the time and endured the Hongerwinter like so many others, making flour for bread and biscuits out of dried tulip bulbs. As an adult she described surviving the starvation with anemia, respiratory problems, and edema, and attributed health problems throughout her life to the malnutrition she endured in 1944.
Did the first settlers in North America arrive across the Bering Strait several thousand years ago? Where and when did Homo sapiens coexist and interbreed with Neanderthals? How old are we as a species, and how, exactly, do we define where we were “born”? The study of human DNA is unveiling astonishingly novel insights into such questions,
A secret history is truly hidden in the mosaics of our genomes, but caveat emptor. No scientific test exists that will tell you where the DNA that you would come to inherit was precisely located in the past. Human history is replete with the fluid movement of people, and tribes and countries and cultures and empires are never, ever permanent.
If you’re a human being on Earth, you almost certainly have Nefertiti, Confucius, or anyone we can actually name from ancient history in your tree, if they left children. The further back we go, the more the certainty of ancestry increases, though the knowledge of our ancestors decreases. It is simultaneously wonderful, trivial, meaningless, and fun.
Our findings suggest a remarkable proposition: no matter the languages we speak or the color of our skin, we share ancestors who planted rice on the banks of the Yangtze, who first domesticated horses on the steppes of the Ukraine, who hunted giant sloths in the forests of North and South America, and who laboured to build the Great Pyramid of Khufu.
But, as with the Human Genome Project, part of the deal is that when you sequence these chunks of DNA, they become public. These ancient genomes are published as databases, free for all to plunder. Geneticists don’t have to go near a fossilized bone or a dank cave nowadays to quiz the genetics of our millennia-dead ancestors. You just need the Internet.
The second key comparison was to try to establish what the ancestral distance was between us, them, and Neanderthals. The way to do this is to look at a stretch of DNA and compare the precise sequence in several species. Very simply, the more similar they are, the more closely related the owners are. This applies at every level of living thing, from twins to bacteria.
To make inroads into this uncharted continent of genomics, we must first tackle the legacy of European colonialism with caution, openness, and fortitude. This kind of wisdom—rarely to be found in academic textbooks of genetics—catapults Rutherford’s book beyond the realm of popular science writing into the domains of philosophy, history of science, and cultural studies.
In contrast to the scraggy Y chromosome, mitochondrial DNA (mtDNA) is only passed from mother to child. The sperm swims along with only half the genetic information to make a new person—twenty-two chromosomes and an X (if that child is to be a woman) or a Y—and wheedles its way into the egg, which also carries twenty-two chromosomes and an X, and also the mtDNA of the mother.
Even when we know the genome intimately, and the patterns of inheritance, and the history of the DNA, and the migration patterns of the people who carried it, and evolutionary pressures that led to the perpetuation of the genes and the phenotype—even when we know all that, how it manifests can still be mysterious and surprising. Anyone who says differently is selling something.
In May 2016, one study sampled over 300,000 people looking for genetic markers that associated with how long people stay in formal education. They found 74 genetic locations of statistical significance. They only account for a very small proportion of the reasons why people stay in school, but alongside motivation, parenting, intelligence, and a host of other factors, DNA is one.
how some genetic genealogy companies will sell you kits that claim to grant you membership to historical peoples, albeit ill-defined, highly romanticized versions of ancient Europeans. This type of genetic astrology, though unscientific and distasteful to my palate, is really just a bit of meaningless fantasy; its real damage is that it undermines scientific literacy in the general public.
almost all the genome is not genes at all. The exome—the DNA in a genome that encodes actual proteins that perform the jobs of living—constitutes less than 2 percent of the total amount of DNA that you carry. Imagine that in a novel: It’s as if there were just 300 meaningful sentences in Dostoevsky’s Crime and Punishment, and the rest of the 211,591 words were largely incomprehensible twaddle.
It doesn’t matter whether we are talking about criminality, or psychological characteristics, or psychiatric disorders, or perfectly normal human behaviors like political bent, or susceptibility to alcohol, or being gay or anywhere on the spectrum of sexual preferences, the biology that is revealed by genetics are not causes, or triggers, or foundations. They are potential factors: probabilities.
The “Paleo Diet” is a popular fad that eschews processed foods and carbohydrates in favor of the only foods imagined to be available to the hunter-gatherers of the Paleolithic: no dairy or processed grains, no lentils, beans, peas, or other human-designed veg. Nuts are OK, but no peanuts, as they’re a farmed product. It is almost certainly built on bunkum foundations, as indeed most fad diets are.
Charles Darwin formulated his idea 50 years before genes, 100 before the double helix, and 150 before the human genome was read. But they all say the same thing. Life is a chemical reaction. Life is derived from what came before. Life is imperfect copying. Life is the accumulation and refinement of information embedded in DNA. Natural selection explains how, once it had started, life evolved on Earth.
DNA changes over time in a relatively predictable manner, like a slowly ticking clock, and so by taking two sequences that are similar but different, we can estimate how long ago they diverged. This technique is not perfect, but it has value in broad terms. In the case of this first study of Neanderthal DNA, the age of the divergence between us and them was put at between 550,000 and 690,000 years ago.
In its inception, farms were subsistence smallholdings, territories carved out of cleared forests and walled fields, and permanent residences. Crops, by their nature, are seasonal, and with farming came a need to plan, to store foods in pots and jars and silos for lean years. With these plans came surplus, some years, and that draw would bring others into the bountiful communities, which would grow and flourish.
A thorough 2014 review by the Brazilian sports scientist Rodrigo Vancini of the scientific literature on the genetics of African athletes concluded that the studies of the variation in these two genes, the ones most frequently associated with black sporting success, “do not fully explain the success of these athletes. It seems unlikely that Africa is producing unique genotypes that cannot be found in other parts of the world.”
Alfred Sturtevant, one of the giants of genetics in the first half of the twentieth century, had first suggested tongue rolling as a Mendelian trait in 1940, a single allele bestowing the ability on its bearer or not. After the twin studies he, like a good scientist should, changed his mind, and said in 1965 that he was “embarrassed to see it listed in some current works as an established Mendelian case.” It is still taught in schools today.
Even the definition of a gene is not rock solid either. The betting book specified sections of DNA that coded a protein. Nowadays we know of many bits of DNA that only encode that supposed intermediary molecule RNA, and which never make it to the status of a protein, but nevertheless have essential biological functions. Are they genes? Well, probably, sort of. As ever, biology turned out to be more complex and interesting than we had imagined.
For most of human history lactase has been active only in babies. After weaning, the gene’s activity is radically reduced, and as a result, for most adults, for most of human history, milk has been off the menu. Most people, for most of human history, will have experienced a full deck of problems that come with drinking milk past weaning. Symptoms include bloating and cramps, vomiting, diarrhea, flatulence, and borborygmus, which is a technical word for a rumbly tummy.
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 wing-flap equivalent to a single character, the width of this period<.>
the real kicker came with the revelation that Denisovan DNA was alive and well in contemporary Melanesians—the indigenous people of Fiji, Papua New Guinea, and a scattering of islands off the northeast coast of Australia. Just as the Neanderthals left their permanent mark in me and you if you are of Eurasian descent, these other people, known only from this single bone, imprinted their genetic mark through the ages in the ancestors of these island people, up to 5 percent of their genomes.
It matters too because as access to our genomes becomes quicker and cheaper, we are presented with raw data—risk factors for diseases and characteristics. It’s easier to fork out £100 for this than it is to learn the complexities of genetic pathways, and epigenetic interactions with the environment, and the statistics that underlie risk and population dynamics. We perpetuate myths by clinging to these simple stories, and fail to bathe in the wondrous complexity of what it means to be a human.
No one will ever find a gene for “evil,” or for beauty, or for musical genius, or for scientific genius, because they don’t exist. DNA is not destiny. The presence of a particular variant of a particular gene may just have the effect of altering the odds of any particular behavior. More likely, the possession of many slight differences in many genes will have an effect on the likelihood of a particular characteristic, in consort with your environment, which includes all things that are not DNA.
It’s only because of the presence of Europeans from the fifteenth century onward that we even have terms such as Indians or Native Americans.* How these people came to be is a subject that is complex and fraught, but it begins in the north. Alaska is separated from Russian land by the Bering Strait. There are islands that punctuate those icy waters, and on a clear day US citizens of Little Diomede can see Russians on Big Diomede, just a little over two miles and one International Date Line away.
Support for eugenics spanned the political spectrum. William Beveridge, principal architect of the welfare state, whose ideas would form the foundations of the National Health Service, said: Those men who through general defects are unable to fill such a whole place in industry are to be recognized as unemployable. They must become the acknowledged dependents of the State . . . but with complete and permanent loss of all citizen rights—including not only the franchise but civil freedom and fatherhood . . . George
Red hair is caused by changes in a single gene, and exists in the overall global population at about 4 to 5 percent, making it beautifully unusual. Its increased prevalence in Scots (and the Welsh and English, and other northern European populations) is probably due to a degree of isolation in an ancestral group at some point in our ancient history, but we don’t really know. Around 40 percent of Scots carry at least one copy of this allele, and one in ten are redheads, but worldwide it is the most unusual hair color.
The people of Tibet carry adaptations to living at altitude, as they do in the deeply inhospitable plains around Everest with its lower levels of oxygen. The people of China to the north and India to the south do not. Mostly, that adaptation is crystallized in a gene called EPAS1, which sits in a region of DNA whose sequence is notably different from the Tibetans’ neighbors. By comparing this highly unusual bit of DNA to other local and global known sequences, it seems that this adaptation was plucked from the Denisovans.
And the genes themselves are broken up by other bits of DNA, called introns, which don’t encode proteins either. All human genes are punctuated with introns, and sometimes they are longer than the actual gene itself. It’s a strange thing, to break up a working xxxxxxxxxx text with so many yyyyyy random bits of irrelevant zzzzz guff, and I continually find it impressive that a cell knows to edit it out when going from the basic code of DNA, via the temporary messenger version of the genetic code, RNA, to the fully functional protein.
The stigmatization and persecution of Native Americans continued well into the twentieth century, too. There are too many examples to name, and they span the whole of North America. Because of their proximity to the Japanese, 881 Aleuts of the Alaskan island chain were interned during the Second World War following the attack on Pearl Harbor, their houses burned by US troops to prevent the Japanese from using them. The Aleuts were housed in conditions far worse than the 700 Nazis who were captured in North Africa and imprisoned a few hundred miles away in Alaska.
Marie Stopes is known today as a champion of women’s reproductive rights, and her name adorns hundreds of clinics worldwide that provide essential support for women and their choices regarding pregnancy. But she held some horrifying views, arguing forcefully for the compulsory “sterilisation of those unfit for parenthood,” particularly the Irish in London. During the 1930s, she wrote love poetry to a rising European politician in praise of his policies, which included reform of his country’s population structure using eugenics as part of their radical plans. His name was Adolf Hitler.
we don’t genuinely know if ginger-hairedness is a mutation that has a physiological advantage. It is unknown if it is an adaptation to northern climates, to the beloved gray weather of Scotland or Scandinavia. It might be sexually selected, as despite the lazy mockery that red hair sometimes invokes, some of us find it enormously attractive. It might be that the mutation, random as they all are, was neutral, and had no noticeable effect, but drifted in populations largely isolated somewhere in the northern realms of Europe, and became fixed in these populations at the low, special frequencies we see today.
For Native Americans, this is not their culture. Not all believe they have always been in their lands, nor that they are a static people. But for the most part, the narrative of migration does not threaten European identity in the same way that it might for the people we called the Indians. The scientifically valid notion of the migration of people from Asia into the Americas may challenge Native creation stories. It may also have the effect of conflating early modern migrants from the fifteenth century onward, with those from 24,000 years earlier, with the effect of undermining indigenous claims to land and sovereignty.
The great irony is this: The science of genetics was founded specifically on the study of racial inequality, by a racist. The history of my field is inextricably intertwined with ideas that we now find toxic: racism, empire, prejudice, and eugenics. Like all true stories and histories, like all real family trees, what follows also weaves a meandering path. All geneticists, all statisticians,* and in fact all scientists owe this Victorian racist a profound intellectual debt, for he was a genius on whose foundations much of the modern world rests. His name was Francis Galton, and as all the great stories in biology do, it begins with Charles Darwin.
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 humankind, as we have roamed across land and oceans, and oceans of time, into every corner of the planet. Geneticists have suddenly become historians.
simple as this, and much more interesting. The protein is 317 amino acids long, and there are several different mutations, all of which switch eumelanin to phaeomelanin. All human proteins are made up from different combinations of 20 amino acids, each of which is encoded in three letters of DNA in a gene. In MC1R, if at position 151 you have the amino acid cysteine instead of the more common arginine, you have red hair. If at position 294 you have a histidine instead of an aspartic acid, you have red hair. There are several other mutations that I won’t list here that have the same effect, but this goes some way to explain why not all red hair is the same.
The absence of lactase, or its reduced activity, means that the lactose doesn’t get digested in the small intestine, so it passes into the colon, where it encounters bacteria that can break it down and it ferments, causing gas buildup. That’s the direct cause of the bloating and fartiness, but also the increased pressure triggers diarrhea, and so on. This is called lactose intolerance, and admittedly though not particularly pleasant, it’s not the worst condition someone can have, and is pretty normal for most people if they drink milk into adulthood. Which is why most people don’t. Except if you’re of European descent. Your lactase continues to work throughout your life.
Elements of the genetics of eye color are true. Brown is indeed dominant over blue, and blue eyes are a recessive condition. Nevertheless, two blue-eyed parents can produce a brown-eyed child, even though it is statistically unlikely. And there’s also another gene that encodes greeny-hazel eyes. What this means is an almost complete spectrum of eye color from the palest blue to the darkest brown, and though much of the variation in our eyes can be attributed to a relatively simple pattern of inheritance, it is not a straightforward Mendelian trait. So far, ten other alleles have been shown to have an effect on eye color, which means that making predictions on what color a child’s eyes will be based on their parents’ is not something I would bet on.
We don’t have to like people to accept that they were correct, or wrong, but Galton remains a tricky fish. Much of his science was utterly brilliant. Much of his insight was equally dazzling. Many of his opinions were horrid. It seems much of his motivation for doing science was born of these ugly views. Science is a process that strives to excise our limited view of the universe and our inbuilt prejudices from understanding an objective reality. Things are often not as they appear to us, but we invented and developed the scientific process to correct our subjective failings: Data is king. Francis Galton’s inclination toward being a data junkie led him to instigate a science that he hoped would affirm his prejudices. The beautiful irony is that it did precisely the opposite.
The Forer effect is a psychological phenomenon where people conclude that broadly true statements are accurate for themselves personally, when they are in fact generically true for many people. In 1948, psychologist Bertram Forer gave his students a personality test, and followed each one with a bespoke vignette of their character. They were then asked to rate their personalized analysis, which they did very positively—an average of 4.26 out of 5. Except they weren’t personalized at all. All the personality sketches were identical, made up of thirteen bland statements that vaguely describe common or desirable personality traits: At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved. This is how astrology works—divination drawn from banality, that we are complicit in. We
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.
At the far end of the American continent lies Tierra del Fuego, the southernmost tip of Chile. There, in 1830, Captain Robert Fitzroy docked an exploration vessel, and as part of hostile negotiations seized three Fuegians, boys named el’leparu and o’run-del’lico, and a girl named yok’cushly. They were given absurd English names—York Minster, Jemmy Button, Fuegia Basket—as part of a bizarre colonial experiment to see if these savages could be “civilized.” Fitzroy took them to England (a fourth named Boat Memory was also taken, but died of smallpox after they arrived; his real, Fuegian name is lost). Fitzroy brought them back a year later on the HMS Beagle’s second voyage. Alongside the three Fuegians was a twenty-two-year-old Charles Darwin, at the beginning of a lifelong journey that would reshape our understanding of life on Earth, and the position of humankind on it.
The media (and to a lesser extent scientists) tirelessly speculate about the evolution of particular traits or behaviors in humans, with neat explanations as to what the advantage they provided was. Many are silly, and ridiculously unscientific—women like pink because as the gatherer half of hunter-gatherer cultures, being able to spot berries would be useful; babies cry at night to prevent their parents from having sex and therefore create competition for them in the form of siblings.* We label these pseudoscientific fantasies adaptationism, or sometimes a form of panglossianism, after Dr. Pangloss from Voltaire’s Candide. An eternal optimist, he suggested there was a reason for everything, and everything had a reason. Hence our noses were shaped as they are to hold glasses in their place, and we had two legs because that perfectly suits the structure of a decent tailored trouser.
Some women might be tetrachromatic. They, through another random chance duplication, have acquired a fourth opsin on one of their X chromosomes. Around one in eight women are estimated to have this extra gene variant, but whether that bestows tetrachromacy is not yet known. The ones who do have this power see colors where we see monotones. It’s a new area of research, and the condition appears to be rare, and poorly accounted for. A few women have been studied, and they seem to see clear differences in colors that are merely shades to normal trichromats. When examining red-green color blindness, the Ishihara test presents a circle containing circles in different hues. Hidden in plain sight (to those with typical vision) is a number, but due to the design of the shades that pick out the number, it is invisible to color-blind people. The tetrachromat tests also rest on the ability to discriminate distinct hues of green where we only see olive.
In early versions of the Book of Isaiah, written in Hebrew, there is a prophecy that uses the word almah to describe the mother of a boy named Immanuel, meaning “God is with us.” Almah has no direct translation in English, nor in ancient Greek, but broadly means “young woman,” or “woman who has not yet borne a child.” By the time of Jesus, the Jews had adopted Greek and Aramaic, and no longer spoke Hebrew. Almah became the Greek Parthenos, which has a more specific meaning as “virgin.” It’s the root of a good biological term, parthenogenesis, used to describe the generation of young in some insects and reptiles in the absence of a male: a virgin birth. But in a mutated translation of a single word, the woman becomes a virgin, and the child becomes the Messiah, and the story of Jesus has instantaneously been transformed. Matthew and Luke render it true in the New Testament, a billion Catholics hold this as gospel, and that’s what we all sing in Christmas carols.
Chang factored that into a further study of common ancestry beyond Europe, and concluded in 2003 that the most recent common ancestor of everyone alive today on Earth lived only around 3,400 years ago. He used two calculations, one that simply crunched the math of ancestry, and another that incorporated a simplified model of towns and migration and ports and people. In the computer model, a port has a higher rate of immigration, and growth rates are higher. With all these and other factors input, the computer calculates when lines of ancestry cross, and the number comes out at around 1400 BCE. It places that person somewhere in Asia, too, but that is more likely to do with the geographical center point from which the migrations are calculated. If this sounds too recent, or baffling because of remote populations in South America or the islands of the South Pacific, remember that no population is known to have remained isolated over a sustained period of time, even in those remote locations.
I believe that we don’t have the language that allows us to align how we talk about race and what genetics and evolution has shown. Genetics has revealed that human variation and its distribution across the planet is more complex and demands more sophisticated squinting than any attempts to align it with crude and ill-defined terms like race, or even black, or white. It is for this reason that I am comfortable stating that from the point of view of a geneticist, race does not exist. It has no useful scientific value. In science we crave precision, in measurement and in language. The urge to categorize is very human, and much sought after in science. We don’t have a definition of life; we have inadequate definitions of species. Life does its best to undermine our noble attempts to categorize living and the living—this is what makes it exciting. Yes, variation that we see when measured by scrutiny of the genome broadly matches large landmasses, but even with oceans as barriers, these boundaries are not sharp, and still only account for a fraction of the differences between individuals. To
In June 1997, J. K. Rowling introduced the world to a boy named Harry Potter and his best male friend Ron Weasley. Ron has many ginger-haired siblings, including identical twin brothers Fred and George. Three weeks after that first Harry Potter book was published, and presumably a magical coincidence, the first major study of ginger-haired twins was published, including twenty-five pairs of Weasley-ish twins. Three major variants were identified that associated very strongly with red hair, but something interesting emerged from the control group. These included dizygotic twins who were discordant for red—that is, nonidentical twins, one a ginger, the other not. Five out of thirteen of these tested had identical MC1R genes. As was beginning to become abundantly clear at that time, just the presence of a redhead allele was not enough to guarantee a redhead. Genes never work in isolation, and almost never have just one role. The discordance of these twins showed that there must be other genetic modifiers that powerfully influence the expression of the MC1R gene to the extent that the phenotype can be either red or not.
in my opinion the HGP was one of the greatest scientific endeavors ever undertaken. It worked, and came in under budget, and on time. It was a visionary idea, a public project paid for by you, for all humankind. The sequences are freely available to everyone (with an Internet connection) in perpetuity. James Watson, John Sulston, and Francis Collins and a host of other top geneticists had seen the vision ahead as the only sensible way to proceed. The biomedical charity the Wellcome Trust knew it too and fought hard for funding a cohesive plan that would ultimately deliver the foundations on which biology would be built in the twenty-first century. The HGP fundamentally changed the way biology is done: Huge international collaborations are now normal and expected in science. Projects that include many disciplines, and many organisms, are the bases of research that delves into diseases, basic biology, evolution, and therapies, and all are underwritten by this colossal DNA database that was created. With hindsight, it is difficult to conceive of a way that biological science could have continued successfully without the Human Genome Project.
The great nineteenth-century Moravian scientist* Gregor Mendel’s work from exactly the same midcentury time, though ignored until the beginning of the twentieth century, described the rules of inheritance—how characteristics pass down the generations from two parents to one child. In the first few decades of the twentieth century, primarily at UCL, a new breed of biology emerged that combined statistics and Darwin, and formalized the mechanism by which evolution by natural selection occurs. Not long after, DNA was established as the bearer of the genetic material and, in 1953, Crick and Watson revealed that it was constructed like a twisted ladder, the double helix, which not only was built to be copied from generation to generation, but also harbored information, a code that could be replicated every time a cell divides. Many scientists over the 1960s cracked that code, and showed it to be a means of writing and recording the instructions to make proteins, and this gave us an understanding of why diseases occur, and why people look different from each other: A tweak in the genetic code results in a subtly different protein, which may have a visible effect—eye color, skin color, the curl of hair.