On a chilly day in February, Daily Mail readers in the UK were confronted with an unexpected headline, which may have caused some to choke on their kippers: DNA suggests 10,000-year-old Brit had dark skin, blue eyes.
The Mail’s online comments boiled over with outrage, from Cardiff to Huddersfield and beyond.
“Next They’ll Be Saying Jesus Had Dark Skin Just Because He Was From The Middle East!”
“This is political correctness gone mad!”
“You can’t tell what colour someone’s skin is from their bones. Bones are white.”
“LEFT WING TRICKERY”
“Sounds all to [sic] convenient and completely unprovable without a time machine. So like where did all the white people come from?”
“What’s to say that the person was not a foreign visitor?”
One armchair biologist wrote cuttingly: “Absolute nonsense – it takes longer than 10,000 years to be white.”
The posts are impressively clueless about basic genetics – so much so, they provide a window into the world before genetic science was understood at all. Many evolutionary biologists would once have agreed with the Mail reader who declared that it takes longer than 10,000 years to be white. But now genetic science does exist, and the story it tells would horrify him.
Studies today support a pretty simple notion about skin colour: that it is an adaption to protect skin from sunlight, which can damage DNA and fertility levels. Dark pigments shield molecules in the skin from intense ultraviolet light. In colder, darker places, on the other hand, people need more sunlight to make the vitamin D their body needs.
The further we go from the Equator, the lighter skin becomes, in multi-hued harmony with this theory. Humans come in a range of colours ordained by gene variants for skin colour. These have nothing to do with complex traits such as behaviour. The genes affect our skin – not our sporting ability, stinginess, honesty, kindness, criminality, aggression or intelligence.
We now know that humans are strikingly genetically similar to each other, compared to most other animals. This stems from the fact we were once an endangered species, so rare that a “genetic bottleneck” was created. This is still visible in every human genome.
Any genetic differences we do have are much, much greater between individuals than between groups. There is more diversity within “races” than between them. Under the spotlight of genetic research, the concept of biological race melts away.
White people, it turns out, are recent mutants, their light, white skin a wrinkle-prone adaptation to low Scandinavian light levels. Most of our species’ 300,000-year span has been spent in Africa, where our skins were dark.
The earliest, undisputed white people ever found were blue-eyed, blond-haired “Swedes” buried a mere 7700 years ago. So the skin colour of Britain’s dark-skinned resident, “Cheddar Man”, who lived 10,000 years ago, came as little surprise to geneticists.
No one knows why light skin took so long to become wide-spread in Europe. After all, we had lived there for 33,000 years before the blond Swedes showed up.
Scientists recently confirmed that 8500 years ago, hunter-gatherers in Spain and Hungary still had dark skin, lacking the mutant versions of two genes that lighten Europeans today.
African genetics are little studied, although they are the most interesting of all. All non-Africans, from Polynesians to Peruvians, descended from the small migratory bands that left Africa, the heartland of human genetic diversity. So they – we – inherited a reduced number of genomes, a small subset of the African total.
“In a genetic sense, nearly all of us who emerged out of Africa, gasping for land and air, are even more closely yoked than previously imagined. We were on the same boat, brother,” wrote the geneticist Siddhartha Mukherjee poetically.
This means that a Ghanaian and a Nigerian genome will contain more (tiny) differences than one from, say, a Japanese person and the descendant of freckly Irish migrants, like me.
In the genetic treasure-house of Africa, Tishkoff and her team found eight genetic variants that strongly affect skin colour, from dark to light. And it seems that while some genetic variants for white skin are relatively recent, others are very ancient indeed. One found throughout the world, lightening the skins of both Europeans and the San hunter-gatherers of Botswana, is astonishingly old – older, in fact, than humanity. It emerged roughly 900,000 years ago – some 600,000 years before we did. (DNA that is uniquely ours accounts for a tiny fraction of our genome.)
This means every human alive today can count, as an ancestor, a hominin with this light-skinned variant. The beast was probably protected from the sun by body hair that shielded its light skin from the sun, as with chimpanzees today. Because under their dark, hairy coat, chimps are white.
But when we evolved in Africa 300,000 years ago, we already had inside our genomes a palette of skin-colour hues worthy of Gauguin. To speak of a “black” person in terms of genetics, then, makes no sense.
Genes can tell us where our ancestors came from – but not what they were like. “The problem with racial discrimination is not the inference of a person’s race from their genetic characteristics,” writes Mukherjee. “It is quite the opposite: it is the inference of a person’s characteristics from their race.”
He cites the African-American maid Aibileen in 2011 movie The Help, who notes: “So, we’s the same. Just a different colour.”
This was published in the April 2018 issue of North & South.