In solving a problem of this sort, the grand thing is to be able to reason backwards.
ARTHUR CONAN DOYLE, A STUDY IN SCARLET, 1887
The ur-redhead, the first carrier among early modern humans of the gene for red hair and thus the genetic grandparent of the vast majority of redheads now alive, appeared on this planet some time around 50,000 years ago.
The world, at this point, was a very different place from how it appears today. Those parts now dry and arid, such as the Sahara, were green and pleasant; areas we think of as temperate, including most of western Europe, were either tundra or under an ice sheet. Stomping or slinking across that ice sheet went the fantastic mega-fauna of the Later Stone Age, or Upper Paleolithic period—woolly mammoth, giant elks, two-hundred-pound hyenas, saber-toothed cats. Trailing after them went Europe’s resident population of Neanderthals, who had lived as hunter-gatherers in this landscape for 200,000 years; and creeping cautiously along as a distant and possibly rather puny-looking third came the first early modern humans.
These early humans had left Africa some 10,000 years before. They had already created populations in the Middle East and Central Asia; they were to explore around the coastlines of the Indian subcontinent; reach as far across the Pacific as Australia and as high as Arctic Russia; find toeholds in the Far East; and at some point cross the land bridge into what is now North America. Their expansion was driven (along with, one might suspect, hunger or greed) by an event referred to by paleontologists as the Upper Paleolithic Revolution. What this term encompasses is a step-change in tool-making, from basic stone implements to highly specialized artifacts of bone or flint that range from needles to spearheads; evidence for the first purposeful engagement in fishing; figurative art, such as cave-painting, along with self-adornment and bead-making; long-distance trade or bartering between different communities; game-playing; music; cooking and seasoning food; burial rituals; and in all probability at this date, the emergence of language.
There is no one reason why this evolutionary jump happened when it did, nor even a consensus as to when or where it began. It may have been driven by changes in climate, as the ice sheets receded or grew, causing these early modern humans to create new technologies and survival strategies or perish. It may have been a very gradual process, but simply without a large-enough surviving debris field of earlier artifacts and evidence for us to be able now to judge how gradual; it might have been triggered by some sudden and singular genetic anomaly; or any possibility between these two. We simply don’t know; too much evidence has been lost to us. Melting glaciation and rising sea levels have drowned the evidence of the earliest coastal settlements. All trace of those who may have battled out a nomadic existence on the ice sheets has disappeared. What we do know is that some 40,000 to 35,000 years ago, those people who had settled the grasslands of Central Asia began to explore outward, west and north, working their way from Iran to the Black Sea, up the valley of the Danube, and into Russia and the rest of Europe. With them, along with their new technologies and beliefs and emerging ethnicities, they carried the gene for red hair.
This may come as a surprise. The gene for red hair, for pale skin, for freckles (on both of which more later), did not originate in Scotland, nor in Ireland, despite the fact that in both those places you will now find the highest proportion of redheads anywhere on Earth (Scotland leads the way with 13 percent of the population being redheads, and maybe 40 percent carrying the gene for red hair, while 10 percent of the people of Ireland have red hair and up to 46 percent carry the gene). Logically, the place with the greatest incidence of any particular characteristic would, one might think, be the place where it first came into being, but not in the case of red hair. The gene emerged at some point in time between the migration from Africa and the settling of those grasslands of Central Asia.
We’re able to make this assertion because of a superbly elegant hypothesis known to scientists as the molecular clock. This piece of evolutionary calculus uses the fossil record and rates of minute molecular change to estimate the length of time since two species diverged, charting this over thousands upon thousands of years, if need be. It enables us to calculate not only how long populations have been separate but how separate they are, with each change in an amino acid, or a DNA sequence, being a tick of the clock. Calibrated to the fossil record, the molecular clock makes it possible to estimate the point in geological history when new genetic traits first came into being. Such as, for example, red hair, or the gene for red hair at least, since at this point that is all we are talking about, the gene, rather than its expression, the appearance of red hair itself.6 And the reason for this lies in the fact that the number of individuals making these migrations seems to have been quite astonishingly low.
It’s been estimated that at the time of that final successful migration out of Africa 60,000 years ago, there may have been no more than 5,000 individuals in the entire African continent. The number estimated to have crossed from Africa over the then-shallow mouth of the Red Sea and into the Middle East, whose footprints now lie fathoms deep and whose descendants would become Homo sapiens, may have been no more than 1,000 and could have been as few as 150. There had been other migrations before this one—the fossilized remains of Java Man and Peking Man, or the 1.8-million-year-old remains of Homo erectus recently discovered in Georgia represent earlier offshoots. The Neanderthal population of Europe is thought to have descended from another even earlier common ancestor, shared with early modern humans, maybe 300,000 years before. There may have been many other earlier migrations out of Africa that failed—just as there were many Roanokes before there was a single Pilgrim Father—or if they did not, their genetic traces are still too deeply hidden within us for science to be able as yet to make them out. But even without ice storms and blizzards of a ferocity that would make headlines in Siberia today, even without enormous carnivores, for this nascent population of early modern humans, the world was not only a staggeringly dangerous place to be, but one with precious few others of the species to share it with.7
And how do we know this? Because, despite the many variations in skin, hair, and eye color that loom so large for us, despite the many rich and challenging social and cultural differences across our planet, genetically we are so very undiverse.
Consider, for example, the heather, or Ericaceae. It colors the hillsides about my brother’s house on the Isle of Skye, fills cranberry bogs in Canada, and romps across the foothills of the Himalayas. Heather, cranberry, and rhododendron are all Ericaceae. There are 4,000 different species in total. You need many, many ancestors to create that much genetic divergence. Consider the dog, Canis lupis familiaris. There are nine separate breeds of dog, from wolves and jackals to man’s best friend, snoozing at your feet. The domesticated breed itself encompasses a spectrum of variation from dachshunds to bulldogs to Great Danes. Think how much genetic diversity that requires. Compared to the differences between a Chihuahua and a St. Bernard, what do we offer? Our limbs are always pretty much in the same proportion to the rest of our bodies, as are our facial features. Our skulls do not radically change shape; we do not come some with snouts and some not; our ears do not stand up or flop, or trail along the ground. Yet we have been breeding and interbreeding for millennia. The reason why there is so little differentiation between any one of us and every other one of us, compared to so many other species of fauna and flora, is because the number of genetically unique individuals the process began with was so mind-bogglingly small.8 And the one certainty about red hair is that for a red-haired baby to result, both mother and father have to be carrying the gene, and what is more, both have then to donate that specific recessive gene in sperm and egg. So if the gene for red hair was present in the early human population in the same percentage in which it is found today, with such tiny numbers of people spread out over such a huge area, it might have existed unseen, unsuspected, and unexpressed for generation after generation without any such propitious meeting taking place.
It must also be remembered that in discussing our ancestors of all those many millennia ago, almost nothing can be stated as irrefutable fact. There are a half dozen equally valid theories for every tiny piece of ancient evidence. Do we know, for example, that Homo sapiens was responsible for the extinction of all those giant animals and the disappearance of the Neanderthals? No, we don’t. We know that the arrival of one coincided with the disappearance of the other; we know, for example, that the last Neanderthals in Europe, who were physically far stronger and had bigger brains than the incomers who displaced them, had completely disappeared by 24,000 years ago, the last of them dying in remote caves facing the sea on the coast of Gibraltar. Looking at our more recent actions on this planet we may conclude that we’re a depressingly good candidate for the prime suspect; but the extinction of the cave hyenas and saber-toothed cats (circa 11,000 years ago), giant elk (7,000 years ago), the mammoth (the last herd lived on Wrangel Island, off Siberia, as recently as 1,650 years ago), and of the Neanderthals themselves could equally well have been caused by climate change or by disease as by the effects of our aggression or over-predation. Or it might have been caused by a combination of all these things. We simply don’t know.
All the same. We are an ambitious, covetous, exploitative, and destructive species, and there has rarely been much good in our engagement with anything we perceive as “other.” We interpret difference as threat rather than potential. And sadly, our race is not alone in that.
The El Sidrón caves are in northern Spain, inland from the coastline of the Bay of Biscay. The nearest large town is Oviedo. During the Spanish Civil War, the caves were used as hideouts by Republican fighters. They have always attracted the curious and intrepid, and when in 1994 what appeared to be two human jawbones were discovered in the gravel and mud on the floor of one of the caves, it was assumed that as the remains were in such good condition they were the tragic relics of some misadventure from the conflict of 1936–39—the victims of some forgotten Civil War atrocity.
The bones were indeed evidence of an atrocity, but of one much, much longer ago. The remains of twelve individuals—three men, three women, three teenage boys, and three children, including an infant—were those of an extended family group of Neanderthals who had presumably been ambushed outside the cave, killed, dismembered, and then cannibalized, the flesh removed from their bones with sharp flint knives, the long bones split to get at the marrow. It’s presumed they must have strayed into the hunting territory of another, rival group of Neanderthals and paid this dreadful price. Or perhaps conditions were so harsh it was a simple case of them or us. After their deaths, some event, perhaps a storm and flash flood, caused the roof of the cave in which their bones were found to collapse, washing their remains into the caverns, and thus they were immured together for another 50,000 years.
Any discovery of so much material in one place is of course of immense importance to archaeologists, but what makes the El Sidrón family so significant a find is just that: these individuals all seem to have been related to one another. They share no more than three groups of mitochondrial DNA, the type that is passed unchanged from mothers to children. In fact all three of the adult men have the same type. And so well preserved were the remains that forensic science could not only extract readable amounts of fragmentary DNA from them but could even fit individual teeth back into jaws. There are similar idiosyncrasies in dentition between the teeth and jawbones of different members of the group, and two of the men shared the same gene variant, which, it is thought, would have given them pale skin, freckles, and red hair.9
We all possess some DNA (maybe 1–4 percent) in common with Neanderthals, and presumably with that original common ancestor, all those many thousands of years ago. If you reach back in time, the percentage of Neanderthal DNA in modern humans seems to increase. Ötzi the Iceman, whose mummified body, frozen into a glacier, was found in 1991 in the mountains of the Austrian-Italian border and who died in about 3,300 BC, had more Neanderthal DNA than today’s modern humans. Not a huge amount (it’s been estimated at 5.5 percent), but a statistically significant one.10
It would be very neat, therefore, to assume that the gene for red hair as it is found in most redheads today is a Neanderthal characteristic, and that when the two species, Neanderthals and early modern humans, met and interbred (scientific thought goes back and forth on this point, but let’s assume usual things happen most usually), the gene was transferred over. It would be very neat; and given the redhead’s reputation for violent bad temper, it’s a theory that has given amusement and much satisfaction to many non-redheads since the first days of anthropological science back in the nineteenth century. It is still encountered time and again in discussions of red hair today, but it is also completely wrong. The genetic mutation that produced the red-headed men from El Sidrón is different from that found in redheads today. It is instead an example of a phenomenon where what appears to be the same result stems from very different causes—something else we will be encountering again. In any case, the far more fundamental point of interest with the red-headed Neanderthals of El Sidrón is not the hair—it’s the freckles. It’s the skin.
The gene that today results in the red hair of almost every redhead on the planet sits on chromosome 16, and if you have red hair, it’s because the version you have of that gene is not working as well as it might. Working perfectly, that MC1R gene, or melanocortin 1 receptor, to give it its full name, would give you brown eyes, dark skin, and an ability to withstand strong sunlight without developing sunburn, sunstroke, or worse. It would do this by stimulating the production of a substance called eumelanin, which colors dark skin, dark eyes, and dark hair. However, MC1R is fritzy. Like a bad internet provider, it flips in and out. If you have red hair, it is almost certainly (there are rare medical conditions that produce red hair, and in the Solomon Islands in the Pacific, an entirely different genetic mutation gives some islanders the most striking gingery-blond afros) almostcertainly, therefore, down to the fact that you carry two copies of a specific recessive variant of the MC1R gene that dials eumelanin production (with all its protective benefits under strong sun) right down, replacing it with yellow or red phaeomelanin, in an extraordinarily complex set of variants that determines the color of individual hairs on your head and of individual cells in your skin.
MC1R, however, is not alone in this process. There is another gene, HCL2, on chromosome 4 (rather unpoetically, HCL2’s full name is simply “hair color 2 [red]”), that also contributes to red hair. Moreover (I did warn you this was complex), while red hair is indeed caused by a recessive gene, there are many possible variants, from recessive red to fully dominant brown or black, with an equal number of manifestations of so-called “codominance” in between.
Thus, many a blonde or brunette has freckles. Many brunettes also have a red tint to their hair, or rather, hair cells that are individually and one by one a mix of eumelanin- and phaeomelanin-producers. A man can have brown or blond hair on his head, yet a beard that grows in red (and very annoying some of them seem to find it, too). This pairing of, say, brown hair, freckles, and red beard is known as “mosaicism,” which describes it pretty much perfectly. You can have red hair in any shade from palest strawberry blond to deepest chestnut. It can come hand in hand, as it were, with blue/green eyes and pale skin and freckles, as it has with me, or with amber eyes, or hazel, or dark brown. A recent survey undertaken by Redhead Days, who run the largest annual festival of redheads in the world, uncovered the fact that up to a third of those who responded classified their eye color as hazel or brown. And (and this is where things get really interesting) it can come with skin dark enough to protect you from sun that would send many another redhead running for sun hat, sunglasses, and sunblock. In general, redheads and strong sun most emphatically do not mix. If you look back at the Redhead Map of Europe, at the beginning of this book, you will see how suddenly the incidence of red hair drops off below that forty-fifth line of latitude. But Afghanistan, Morocco, Algeria, Iran, northern India and Pakistan, and the province of Xinjiang in China all have ancient, native populations of redheads. Shah Ismail I (1487–1524), commander in chief of the Qizilbash and founder of the Safavid dynasty in Iran, was described by the sixteenth-century Italian chronicler Giosafat Barbaro as having reddish hair, and indeed his portrait in the Uffizi, by an unknown Venetian artist, shows a man with an aquiline nose, red beard, and red mustache. The sixteenth-century Shahnama of his Safavid successor, Shah Tamasp, now in the Metropolitan Museum of Art, shows a red-bearded hero, Rustam. In the ancient world Alexander the Great’s Roxana, who was born in Bactria, now northern Afghanistan, and who the Napoleon of the ancient world married in 327 BC, was reputedly a redhead; the present-day Princess Lalla Salma of Morocco perhaps gives an idea of quite how beautiful she might have been. Then there is that different shuffle of the genetic pack in the Solomon Islands in the Pacific—which, again, comes with skin dark enough to withstand in this case tropical sun. (Fig. 29). In the history of red hair, what you might call its typical Celtic manifestation—pale skinned, blue eyed, suited for cool and rainy climes and cloudy skies—may not originally have been typical at all. In fact pale skin in early modern humans has been estimated as having appeared as recently as 20,000 years ago.11
Most genetic mutations die out rather than become more common, and if they are as unadvantageous as pale skin under fiercely sunny African skies, they take their unfortunate carriers with them. It may be going too far to characterize Mother Nature as smart, but left to herself she does have a heartlessly effective way of cleaning out the gene pool. If you’re not fit to survive, you won’t. But if a genetic quirk confers a benefit upon those carrying that gene, it, and they, will flourish. And pale skin under Northern skies does exactly that. If your eumelanin production is dialed back, if you have pale skin rather than dark, your body will be much more effective at synthesizing vitamin D, using whatever sunlight is available, than if your skin were darker. And as the ice sheets retreated, and that growing population of early modern humans moved from Russia into Scandinavia, and eventually into the whole of northern Europe, the absence of strong sun in these climes allowed the MC1R gene to mutate into what geneticists term “dysfunctional variants” without these variants proving fatal to those carrying them. In fact the farther north this population went, the more advantageous pale skin became. If you have enough vitamin D, your skeleton develops as it should. If you do not, your bones are soft and stunted, and as you learn to walk, your legs bow under your weight. This is osteomalacia, or rickets. In adults, it causes calcium to leach away from your bones; in children, it cripples you. Women of child-bearing age who suffered from rickets when they themselves were children have distorted pelvises that make carrying a pregnancy to full term difficult and childbirth hazardous, if not fatal (Fig. 3).
Fig. 3 Medical illustration of the pelvis of a woman suffering from rickets, showing the narrowed and distorted birth canal.
Communities that eat most of their protein in the form of meat, as with the early hunter-gatherers, rarely suffer from vitamin D deficiency. But the tendency in the early modern human population was to settle; to become farmers, to grow and eat grain. In these circumstances, pale skin helped keep you strong and healthy. In particular, it gave a significant advantage to women during pregnancy and breast-feeding, when their bodies’ demand for vitamin D was at an all-time high, which along with all the other ancient and instinctive associations of the color red (fire, blood, passion, ripeness) does rather open the question as to whether the often highly sexualized image of female redheads might not start here, with the simple fact that choosing a redhead as a mate meant you bred successfully, and that your pale-skinned children, themselves now carrying the gene for red hair, did the same.12
This is also where the random mysteries of “genetic drift” come into play. Genetic drift is the term used to describe random changes in the frequency of a genetic variant, or “allele,” as it is also known within a given population. There is some essential scientific terminology to become familiar with here, and perhaps the simplest way to conceptualize it is if you cast your mind back to your first school photograph. You, seated there cross-legged on the ground, squinting at the sun, are an individual allele, an individual genetic variant. The front row of you and all your classmates make what is known as a haplotype—a cluster of linked alleles, all of whom are likely to be inherited together. Your haplogroup would be everyone in the school.
If a population is large, it can take a considerable time before random changes in the frequency of an allele become noticeable, and indeed as they are governed only by chance, and their frequency can alter one way or the other from one generation to the next, some may never result in any noticeable change at all. But in a small population, the fixation of a particular allele within that group, such as (for example) red hair, can happen very rapidly indeed. In small populations, in borderlands, in any community set apart from the great genetic ebb and flow of the human ocean, in places such as Ireland or on the west coast of Scotland, its effect can be established within just a few generations. Add to this the not-random-at-all mysteries of sexual selection, and the fixing of red hair among these liminal populations, and among liminal populations in the Levant, the Caucasus, and the Atlas Mountains, becomes a phenomenon that exists logically and obviously. As of course it also does among the famous Wildlings in Game of Thrones. Redheads: guaranteed throughout history to crop up in the last place you expect them.