A Brief History of Everyone Who Ever Lived: The Stories in Our Genes

by Adam Rutherford

Britain has been host to humans for almost a million years.

The Welsh, they look distinct from the rest of Britain too, and within Wales, the north and south settle apart as well. Even within southern Wales, the divisions of culture are borne out in the genome. An invisible line slices through the southernmost tip of the Gower Peninsular, at the bottom of Wales. It bisects Pembrokeshire to the point where that county meets its neighbour to the east, at the River Taf north in Carmarthenshire. Since the sixteenth century this domain has been known as Anglia Transwalliana – Little England Beyond Wales – and the boundary called the Landsker Line. It’s a language barrier more than anything else, and has no formal or legal status, though it has lasted a thousand years. To the south is a pocket of English speakers, whereas the rest of Wales spoke Welsh (at least historically; English is spoken everywhere today). It’s drifted over the centuries, a few miles north or south depending on the local movement of people and traditions, but largely it’s preserved as a vague border a few miles deep. There’s a neat-ish line of forts that map roughly along the line too, Norman castles from Roch on the west to Laugharne on the east, but it’s a stretch to say these were frontiers protecting this informal border.

The Celts are a people whom we romantically think of as being tough Welsh, Scottish, Breton or Irish, with a style of art and culture instantly recognizable with often abstract twisted shield bolts and crosses. They slide up the west coast of Britain, from Cornwall, through Wales and into Scotland, Picts to the north, Saxons to east. But they’re not a cohesive group of people at all. According to the British genome, Scottish Celts are more different to Welsh Celts than either are to the English. The same goes for the Cornish, who resemble the Breton Celts 250 miles to the south in France.

You are descended from Vikings, because everyone is.

The north Welsh are as different genetically from their southern compatriots as southern Englanders are from the Scottish, or the people of Devon from the Cornish. Even if you’re more Welsh than your neighbours, it’s only in the details, and you’re still part Viking, Saracen, Angle, Saxon and, as we shall soon see, part Holy Roman Emperor.

Since the end of the era of settlement, there’s been very little immigration into Iceland of note. The population has never topped 400,000. These are all matters which make genealogy and genetics significantly easier. The Icelanders knew this, and decided with great foresight to add DNA to their database of identity. Theirs is now the most comprehensively studied genome of any people, both ancient and modern.

Pandemics are always just around the corner, but it’s now unlikely that plague will devastate the lands as it did repeatedly in history.

Charlemagne, Carolingian King of the Franks, Holy Roman Emperor, the great European conciliator; your ancestor. I am making an assumption that you are broadly of European descent,

I can say with absolute confidence that if you’re vaguely of European extraction, just like cinema’s greatest Prince of Darkness, you are descended from Charlemagne too. Hail to the king!

The simple logic is that there are more living people on Earth now than at any single moment in the past, which means that many fewer people act as multiple ancestors of people alive today.

Sometime at the end of the thirteenth century lived a man or woman from whom all Europeans could trace ancestry, if records permitted (which they don’t).

if we could document the total family tree of everyone alive back through 600 years, among the impenetrable mess, everyone European alive would be able to select a line that would cross everyone else’s around the time of Richard II.

One fifth of people alive a millennium ago in Europe are the ancestors of no one alive today. Their lines of descent petered out at some point, when they or one of their progeny did not leave any of their own. Conversely, the remaining 80 per cent are the ancestor of everyone living today. All lines of ancestry coalesce on every individual in the tenth century.

if Charlemagne was alive in the ninth century, which we know he was, and he left descendants who are alive today, which we also know is true, then he is the ancestor of everyone alive in Europe today.

DNA is the bearer of biological ancestry, and you get all of your DNA from your two parents, pretty much a 50:50 split. They in turn got all of their DNA from their parents, so one quarter of your DNA is the same as a quarter of each of your grandparents. If you have a cousin, then you share around an eighth of your DNA, as you have a pair of grandparents in common.

Remember that DNA gets shuffled when a sperm or egg is made, and every single shuffle is different, but it’s quite clumsy shuffling. In the newly shuffled deck, that is, your own personal genome, big chunks of it are the same as your father or mother. The more closely related two people are, the more DNA they will share in big chunks.

the most recent common ancestor of everyone alive today on Earth lived only around 3,400 years ago.

We see families as discrete units in our lifetimes, which they are. But they’re fluid and continuous over longer periods beyond our view, and our family trees sprawl in all directions.

no matter the languages we speak or the colour 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.

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 alive in the tenth century who left descendants is the ancestor of every living European today, including Charlemagne,

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 genes of your forebears have very little influence over you. Unless you carry a particular disease that has passed down the family tree, the unending shuffling of genes, the dilution through generations, and the highly variably and immensely complex influence that genes have over your actual behaviour mean that your ancestors have little sway over you at all.

There are only really a couple of definitive unequivocal statements that we can make about your origins in the deep past. The first is that 100,000 years ago we were all African. At that time, there were no Homo sapiens anywhere on Earth apart from in Africa, as far as we know.

The second is about Neanderthals. 23andMe allocated 2.7 per cent of my genome to a Neanderthal origin, which is bang on average for most Europeans (though higher than the estimates from published academic science).

everyone in Europe has Viking ancestry. Admittedly, the proportions do vary between people and these differences correlate with geography.

if you are white, you have Viking ancestry.

the tendrils of ancestry that sprout upwards from you become unfathomably enmeshed the further back you go, until all reach all people a thousand years ago.

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.

The truth is that we all are a bit of everything, and we come from all over.

A thousand years ago, we Europeans share all of our ancestry. Triple that time and we share all our ancestry with everyone on Earth. We are all cousins, of some degree.

these descriptions of historical people holds steadfast, and only a thousand years ago your DNA began being threaded from millions from every culture, tribe and country.

If you want to spend your cash on someone in a white coat telling you that you’re from a tribe of wandering Germanic topless warriors, or descended from Vikings, Saracens, Saxons, or Drogo of Metz or even the Great Emperor Charlemagne, help yourself. I, or hundreds of geneticists around the world, will shrug and do it for free: you are. And you don’t even need to spit in a tube – your majesty.

Richard III is now the oldest person to be unequivocally identified in death.

We shed DNA all the time. Your DNA is on the pages of this book, mine on the keys on this keyboard and in the microphone of my mobile phone, as it’s even transmitted in minute, but detectable quantities, on our breath.

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.

William Wilberforce had driven the Abolition of the Slave Trade Act through Parliament in 1807, which largely banned slavery, though only in 1833 was this extended throughout the whole Empire with the Slavery Abolition Act.

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 lovey 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.

The British never did adopt a eugenics policy, despite England being the intellectual birthplace of the idea. Before Darwin and Galton, Thomas Malthus had formally fretted about population growth and control, and therein laid the foundations of improving the ‘stock’ of a people. But in the USA, and a few other countries (notably Sweden), the forced, involuntary and often secret sterilization of undesirables was embraced enthusiastically.

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.

the common origin of all humans alive at only 3,400 years ago, or thereabouts.

In the human genome, in total, there are around 3 billion individual letters of DNA. Of the analogies of scale, the one that gets trotted out most frequently is that this is equivalent to some twenty standard-issue phone books,

we have fewer genes than a roundworm. Or a banana.

Humankind is a species of explorers. For millennia, we’ve built and invented and tested in order to try to understand the world, the universe, us and our place in it.

Sexual behaviour is a spectrum. At one end some people are exclusively homosexual and at the other end some are exclusively heterosexual. Most people are somewhere in between in thought, word or deed. Some people are asexual.

it is not possible to predict the complex behaviours 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.

Five thousand years ago there were 5 million or so of us. By 2025 we estimate a global population of 9 billion.

Darwin’s theory of evolution by natural selection is just that – a theory. Outside science, there is some understandable confusion about what that word means. In science, a ‘theory’ is the best description we have. Unlike the common usage, it’s not a guess, or a hunch, or a hypothesis. It’s the most complete subjective picture of the living world that we have.

What a senseless phrase is ‘curiosity killed the cat’. To be incurious is to be inhuman.

there has never been anyone quite like you before, and there never will be again. Your face, your physiology, your metabolism, your experience, your family, your DNA and your history are the contrivances of cosmic happenstance in a fully indifferent universe. We’re unique in our DNA, but it was drawn from millions of past lives.

that every one of us shares an ancestor who, in the words of Joseph Chang, sowed rice on the banks of the Yangtze or who laboured to build the pyramids.