PHILADELPHIA – In an unprecedented feat of forensic anthropology, European researchers extracted enough DNA from two Neanderthal skulls to suggest their owners sported red hair and white skin back when they were alive 43,000 and 50,000 years ago.
The hair color of humanity’s closest relative might sound trivial, but the finding, announced in Friday’s issue of the journal Science, stunned anthropologists with the sheer power of genetics to reveal what Neanderthals really looked like, and how they behaved. And that, some say, will change the way humanity views itself.
“We are building an image of these Neanderthal people – their physical aspects, cognitive abilities, metabolism, immunity – the range is enormous,” said Carles Lalueza-Fox, of Barcelona, an author of the paper.
Scientists found the first Neanderthal fossils 150 years ago in Germany’s Neander Valley. Since then, enough fossils surfaced to show their lineage branched off from ours about 500,000 years ago, in Africa. It’s a relatively recent split compared with the one our lineage made from the chimpanzees’ line about 6 million years back.
Both human and Neanderthal lineages continued to evolve bigger brains after parting ways. The Neanderthals left behind stone tools, and they almost certainly used fire, but they went extinct about 17,000 years ago.
When a group of scientists led by Svante Paabo of the Max Planck Institute of Evolutionary Anthropology in Germany started attempting to sequence Neanderthal DNA, many regarded the venture as a long shot.
Lalueza-Fox said the team decided to focus on a skin pigment gene, called MC1R, because it was related to one known difference between Neanderthal and modern human history: Neanderthals left for Europe and the Middle East some 400,000 years ago while our ancestors stayed in Africa until about 50,000 years ago.
In Africa, there’s huge evolutionary pressure to retain a certain version of this gene that promotes dark pigment, he said. Anyone with a genetic mistake that interfered with that would be left vulnerable to sunburn and skin cancer.
But in Europe, variations of this pigment gene can thrive and even flourish, since light-skinned people more efficiently produce vitamin D in relatively northern regions. One variant of the gene, for example, is common among Irish people and leads to red hair and pale, freckled skin.
Lalueza-Fox and colleagues found a different variant of the same gene in their Neanderthal samples.
But how do they know this new variant led to red-haired, white Neanderthals? Both the Neanderthal and modern versions hold the recipe for a similarly disabled version of a protein, said Hopi Hoekstra, an evolutionary geneticist at Harvard University.
“It’s like a proof of concept,” said Penns’ Dibble. The finding bolsters the case that scientists really can sequence the DNA from Neanderthal bones, thus shedding light on dozens of other traits.