This is the first reconstruction of a female Neanderthal to be based in part on ancient DNA evidence. Anthropologists have now gone beyond fossils and are reading the actual genes of an extinct species of human.
Neanderthals appeared in Europe about 300,000 years ago but mysteriously vanished ca. 35,000 years ago, shortly after the arrival of modern humans in Europe.
Artists and scientists created Wilma (cutely named for the Flintstones character) using analysis of DNA from 43,000-year-old bones that had been cannibalized. No wonder she looks so peeved. Who wants to go down in history as a half-chewed bone?
The genes associated with pigmentation suggest that at least some Neanderthals would have had red hair, pale skin, and possibly freckles. The traits were likely more common in European Neanderthals, just as they are often seen in modern humans of European descent.
Wilma's genes showed an unknown mutation in a key gene called MC1R, also present in modern humans, said the study's lead author Carles Lalueza-Fox of the University of Barcelona. MC1R regulates a protein that guides the production of melanin, which pigments hair and skin and protects from UV rays.
"European [humans] have quite a lot of variation in this gene — not only red hair variants but also others," he explained, adding that humans have been in Europe for only about 40,000 years. "The Neanderthals, being there at least 400,000 [years], likely accumulated ten times more variation."
Wilma Didn't Mate with Modern Humans
Other Neanderthal enthusiasts have come to the same conclusion: Wilma didn't mix with the new guys in the neighbourhood. So, we'll have to remove the third figure in the famous cartoon (left) -- whether ascent or descent of Man or Ape.
Researchers at the Max Planck Institute for Evolutionary Biology have now sequenced the complete mitochondrial genome — genetic information passed down from mothers — of a 38,000-year-old Neanderthal thigh bone found in a cave in Croatia. The sequence contains 16,565 DNA bases, or "letters," representing 13 genes, making it the longest stretch of Neanderthal DNA ever examined.
The new study shows that at least for the maternal lineage, there are no traceable genetic markers that suggest admixture of Neanderthals and modern humans.
The study author, Richard Green, points out that Neanderthals exhibited a greater number of letter substitutions than modern humans due to mutations in their mitochondrial DNA, although they seem to have undergone fewer evolutionary changes overall. The fact that so many mutations — some of which may have been harmful — persisted in the Neanderthal genome could indicate the species suffered from a limited gene pool. This might be because the Neanderthal population was smaller than that of Homo sapiens living in Europe at the time.
The researchers estimate the Neanderthal population living in Europe 38,000 years ago never reached more than 10,000 at any one time.
"If there were only a few, small bands of Neanderthals, barely hanging on, then any change to their way of life could have been enough to drive them to extinction," Green said. "One obvious change would have been the introduction of another large hominid—modern humans." And he added, "a small population size can diminish the power of natural selection to remove slightly deleterious evolutionary changes."
In short, inbreeding.
Wilma is more than just a token thigh bone.
Created for an October 2008 National Geographic magazine article, Wilma has a skeleton made from replicas of pelvis and skull bones from Neanderthal females. Copies of male Neanderthal bones — resized to female dimensions — filled in the gaps. She is thus the first full-size Neanderthal female reconstructed using the latest information from genetics, fossil evidence, and archaeology.
The shape of her eyes rings especially true: like many modern cold-adapted populations, they seem to have an extra fold of skin which produces a hooded eye appearance: in Asians the fold spreads from the nose side of the eye outward, and in NW Europeans, it spreads from the outside of the eye inward. Wilma is also chubby-cheeked: her facial padding is another cold-adapted feature.
Was her pelvis the death of her?
Meanwhile, at the University of Zurich, Marcia Ponce de León and colleagues pieced together three Neanderthal baby skeletons: one newborn from a cave in Russia and two infants aged 19 and 24 months,from a Syrian cave. In addition, the scientists reconstructed the pelvis of an adult female Neanderthal skeleton found in Israel.
By analysing the skeletons, the team found that Neanderthal babies were born with similar-size skulls to those of modern human babies. However, the shape of the face was different. Even in a newborn baby, the conspicuous protrusion of the forehead that distinguishes Neanderthals was evident.
Putting the baby and the mother together, the birthing process would have been at the limit of what was possible, and the baby's head would have had to turn by a quarter … in order to get through the narrow lower pelvis. According to the scientists, this may explain why modern humans eventually trumped Neanderthals.
Cannibalism wouldn't have helped either!
Update: 24 September 2008(Left) A National Geographer puts the finishing touches to Wilma's reconstruction. The October 2008 issue of National Geographic is now available on-line and it should not be missed by anyone keen on Neanderthals. From this issue:
Since 2000, some 1,500 bone fragments have been unearthed from this side gallery [of El Sidrón cave], representing the remains of at least nine Neanderthals—five young adults, two adolescents, a child of about eight, and a three-year-old toddler. All showed signs of nutritional stress in their teeth—not unusual in young Neanderthals late in their time on Earth. But a deeper desperation is etched in their bones. Antonio Rosas [of the National Museum of Natural Sciences, Madrid] picked up a recently unearthed fragment of a skull and another of a long bone of an arm, both with jagged edges.
"These fractures were— clop— made by humans," Rosas said, imitating the blow of a stone tool. "It means these fellows went after the brains and into long bones for the marrow."
In addition to the fractures, cut marks left on the bones by stone tools clearly indicate that the individuals were cannibalized. Whoever ate their flesh, and for whatever reason—starvation? ritual?—the subsequent fate of their remains bestowed upon them a distinct and marvelous kind of immortality.
See also Chris Sloan's blog, Stones, Bones 'n Things (Chris was for 12 years Art Director and Paleontology specialist at National Geographic; he's now "responsible for for keeping track of a bunch of scientists" on Society-funded projects). On his blog today, he talks about some of the pitfalls -- and pleasures -- of reconstructing how ancient people looked from their bare bones. In Wilma's case, of course, we now have added genetic information which gives real life to her skin colour and hair. He has this to say about her body reconstruction:
The model's beat up appearance and "hunting" pose is consistent with the notion that Neandertal life was rough, injuries were high, and we have no reason to believe that females did not participate in hunts, in one way or the other.
A game old girl -- beat-up but immortal: that's Wilma for you.
* First read about on Dienekes' Anthropology Blog (with interesting comments by Kosmo).