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

by Adam Rutherford

Something in the order of a 107 billion modern humans have existed, though this number depends on when exactly you start counting. All of them – of us – are close cousins, as our species has a single African origin.

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.

By consensus, history begins with writing. Before that we have prehistory – the stuff that happened before we wrote it down.

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 east and north Africa. Writing began about 6,000 years ago, in Mesopotamia, somewhere in what we now call the Middle East.

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.

Dozens of lines of evidence bellow incontrovertibly that we are an ape, with an ape ancestor common to chimpanzees, bonobos, gorillas, and orangutans.

The most famous of these early walkers is Lucy, born around 3.2 million years ago.

Lucy was one of the first members of the species Australopithecus afarensis discovered. We cannot say whether her species was a direct ancestor of us. What we can say is that there were many other primates living at this time, and she looks more closely related to us than any other.

We are genus: Homo; species: sapiens – Homo sapiens: the wise man.

palaeoanthropology – the study of ancient humans –

We anatomically modern humans are generally thought to have evolved primarily in eastern Africa around 200,000 years ago, and emerged out of Africa in our own exodus sometime in the last 100,000 years.

Neanderthals were capable of speech, very probably. The structure of their throats is not dissimilar to our own and, in particular, the discovery of a hyoid bone in the Kebara Cave in Israel in 1989 indicated that their capability of speech must have been similar to our own.

Neanderthals probably had the capacity for speech, like us.

The question of our relationship with Neanderthals has been refined with genetics, in terms of our shared ancestors; our lineage moved away from theirs around half a million years ago. But what DNA analysis revealed more categorically than anything else was that we had sex with them, repeatedly, probably as soon as these two peoples met, and every time afterwards.

humans migrated out of Africa,

the Out of Africa hypothesis, defined by our migration away from the first site of anatomically modern humans.

Our Homo sapiens ancestors inched into Europe around 60,000 years ago,

If you are broadly of European descent, then it is almost certain that you also carry around Neanderthal DNA too.

Neanderthals categorically were also our ancestors.

Anatomically modern humans had sex with anatomically Neanderthal humans on many occasions in our history.

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.

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.

Evidence of humans in Britain dates back almost a million years,

The Neanderthals made their homes all around Europe (see Chapter 1) – in Germany (where the name we gave them comes from), all over France, and scattered in the east of Europe, Wales, Israel and further towards the east.

The oldest genome of a European comes from a 37,000-year-old square-jawed man who washed up on the banks of the mighty River Don in southern Russia.

The record for the oldest complete modern human genome comes earlier and from the banks of another mighty Russian river further

Estimates are that the hunter-gatherers who were all but wiped out by the agricultural revolution numbered around 2 million 12,000 years ago.

By the time of the Roman Empire, there were a quarter of a billion farmers on Earth, and foraging was a living now limited to a couple of million people at most, flung far into the corners a long way from Europe, in Australia, South America and in pockets in Africa.

Eight thousand years ago there were probably about 5 million people on Earth, the current population of Norway.

The first Europeans were the hunter-gatherers who had moved up from Africa via central Eurasia 40,000 years before, and overlapped and mated with the indigenous Neanderthals.

Between 9,000 and 7,000 years ago, we see the genetic fingers of eastern farmers reaching into this population. They didn’t usurp them or wipe them out, though. We see the two populations living not exactly side by side, but at the same time, some hunters, some farmers, and we see the slow integration of genes from the hunters enter into the genomes of the farmers.

then around 5,000 years ago, another major wave of easterners arrive. The Yamnaya came from the Russian Steppes, driving sheep, riding wagons, making bronze jewellery and covering their dead in ochre as part of ritual burials. They came and rapidly their way of life spread into middle Europe, bringing their culture and genes, and their f...

If you are pale skinned, you are almost certainly a product of these three waves of European immigration.

current residents of a geographical area are not necessarily very good representatives of the residents of the deep past. This is obvious if we look at areas that have been subject to migration by modern Europeans: the majority of the peoples of Australia or North America today are from Europe in the last 500 years, and so their genomes are not representative of the indigenous people who were there first.

Most adult humans today, and almost every human in history, do not even have the capability to digest milk.

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.

Except if you’re of European descent. Your lactase continues to work throughout your life.

There are a handful of African populations, some in South East Asia and a few Middle Eastern peoples whose lactase persists, but for the majority of modern humans, milk equals tummy troubles.

By 6,000 years ago, milk had become a part of Neolithic life.

By 5500 BCE, we were making cheese.

Lactase persistence is now effectively universal in Europeans (those African and the Middle Eastern peoples who also are lactase persistent have different mutations and are unlikely to have a common origin). At some point, maybe 8,000 years ago, it was absent.

In parts of Africa, and Australia and the islands of the Indian Ocean, people have the darkest of dark skin, almost black in its true sense. In Scotland, or the north of Sweden, some are so pale as to be almost translucent. All skin tones in between exist in abundance. This is not some liberal fantasy, it’s simply a truth that a Pantone swatch of human skin is a continuum.

At least eleven genes appear to have a direct role in determining skin and hair colour. Overall, it’s all down to the density and type of melanin that you produce.

We pale-skins tan to protect us, in a somewhat post-horse bolting way (so my advice is wear sunscreen), but those in the blazing sun near the waist of the earth are pre-emptively protected by being full of melanin.

Red hair is caused by changes in a single gene, and exists in the overall global population at about 4–5 per cent, 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 per cent of Scots carry at least one copy of this allele, and one in ten are redheads, but worldwide it is the most unusual hair colour.

there is good evidence for pale skin being an adaptation to the cold of the north, but none that red hair is too.

like so many human characteristics, we don’t genuinely know if ginger-hairedness is a mutation that has a physiological advantage.

Neanderthal teeth have been found as far west as north Wales.

the skull found in a pit near a golf course in Piltdown, Sussex, in 1912, was only half man. For a short while he was a celebrity, but turned out to be a shameless fraud, an orangutan’s jaw jammed into an old but modern human skull, the work, probably, of Charles Dawson, who was so desperate to become a proper grown-up scientist, join the Royal Society and gain international repute that he engineered this and other elaborate deceits over many years.