Redheaded strangers

Ancient DNA retrieved from the bones of two Neanderthals suggests that
at least some of them had red hair and pale skin, scientists report
this week in the journal Science. The international team says that
Neanderthals’ pigmentation may even have been as varied as that of
modern humans, and that at least 1 percent of Neanderthals were likely
redheads.

The scientists — led by Holger Römpler of Harvard University and the
University of Leipzig, Carles Lalueza-Fox of the University of
Barcelona, and Michael Hofreiter of the Max Planck Institute for
Evolutionary Anthropology in Leipzig — extracted, amplified, and
sequenced a pigmentation gene called MC1R from the bones of a
43,000-year-old Neanderthal from El Sidrón, Spain, and a 50,000-year-old individual from Monti Lessini, Italy.

“Together with other genes, this MC1R gene dictates hair and skin color
in humans and other mammals,” says Römpler, a postdoctoral researcher
working with Hopi E. Hoekstra in Harvard’s Department of Organismic and
Evolutionary Biology. “The two Neanderthal individuals we studied
showed a point mutation not seen in modern humans.

“When we induced such
a mutation in human cells,” Römpler explained, “we found that it impaired MC1R activity, a
condition that leads to red hair and pale skin in modern humans.”

To ensure that the MC1R point mutation was not due to contamination
from modern humans, the scientists checked some 3,700 people, including
those previously sequenced for the gene as well as everyone involved in
the excavation and genetic analysis of the two Neanderthals. None
showed the mutation, suggesting that Neanderthals and Homo sapiens
followed different evolutionary paths to the same redheaded appearance.

With Neanderthals’ surviving bones providing few clues, scientists have
long sought to flesh out the appearance of this hominid species found
across Eurasia some 28,000 to 400,000 years ago. While anthropologists
had predicted that Neanderthals might have had pale skin or red hair,
the new work by Römpler and colleagues offers the first strong evidence
to support this hunch.

Found in cell membranes, MC1R is a receptor that acts as a switch
between production of the red-and-yellow pigment pheomelanin and the
black-and-brown pigment eumelanin. Modern humans with mutations that
cause complete or partial loss of MC1R function tend to be pale and
red-haired, although many other pigmentation genes can also result in
this phenotype.

In 2006, a team led by Römpler found a mutation in woolly mammoths that
may lead to some blond mammoths; together with her colleagues,
Hoekstra, the John L. Loeb Associate Professor of the Natural Sciences
at Harvard and curator in mammalogy in Harvard’s Museum of Comparative
Zoology, has shown that this same mutation causes light coloration in
mice.

Römpler and Hoekstra are now collaborating to identify genetic
changes responsible for pigment variation in other extant and extinct
species.
“It has only recently become possible to decipher the genomes of
species which became extinct thousands of years ago,” Römpler says.
“The methods used in these Neanderthal and mammoth studies could
provide new insights into the coloration of other extinct hominids,
animals, and plants.”

Römpler, Lalueza-Fox, and Hofreiter’s co-authors are David Caramelli
and Elena Pilli of the University of Firenze; Claudia Stäubert and
Torsten Schöneberg of the University of Leipzig; Giulio Catalano of the
University of Firenze and Universitat Pompeu Fabra; David Hughes, Nadin
Rohland, and Mark Stoneking of the Max Planck Institute for
Evolutionary Anthropology; Laura Longo of the University of Siena;
Silvana Condemi of CNRS; Marco de la Rasilla and Javier Fortea of the
University of Oveido; Antonio Rosas of the Museo Nacional de Ciencias
Naturales in Madrid; and Jaume Bertranpetit of Universitat Pompeu Fabra.

The work was funded by the Spanish Ministry of Education and Science;
the Generalitat de Catalunya; the Max Planck Society; the Deutsche
Forschungsgemeinschaft; the Bundesministerium für Bildung und
Forschung; the IZKF Leipzig; the Studienstiftung des Deutschen Volkes;
and the Autonomous Government of Asturias.