White Europeans could have evolved as recently as 5,500 years ago, according to research which suggests that the early humans who populated Britain and Scandinavia had dark skins for millenniums.
It was only when early humans gave up hunter-gathering and switched to farming about 5,500 years ago that white skin began to be favoured, say the researchers.
This is because farmed food was deficient in vitamin D, a vital nutrient. Humans can make this in their skin when exposed to sunlight, but dark skin is much less efficient at it.
In places such as northern Europe, where sunlight levels are low, the ability to make vitamin D more efficiently could have been crucial to survival.
Johan Moan, of the Institute of Physics at the University of Oslo, said in a research paper: “In England, from 5,500-5,200 years ago the food changed rapidly away from fish as an important food source. This led to a rapid development of ... light skin.”
Moan, who worked with Richard Setlow, a biophysicist at Brookhaven National Laboratory in New York state, said vitamin D deficiency could be lethal. Research links it with heart disease, diabetes, arthritis and reduced immunity.
Their research says: “Cold climates and high latitudes would speed up the need for skin lightening. Agricultural food was an insufficient source of vitamin D, and solar radiation was too low to produce enough vitamin D in dark skin.”
Such findings need to be treated with caution. The history of the colonisation of Europe is highly complex because its climate has been dominated by a series of ice ages, punctuated by warm periods.
This means early humans ventured to Europe not just once but many times over the past 700,000 years, returning each time the ice melted only to be driven back again when it returned.
Furthermore, the ice ages coincided with, and may even have driven, the evolution of modern humans, with several species such as Neanderthals and Cro-Magnons appearing at various times.
The idea that human evolution has often turned on chance mutations is well established. Some researchers have linked the entire evolution of language with mutations in a gene known as FoxP2 occurring about 50,000 years ago.