Mammoths: Blondes and brunettes?

The wool of woolly mammoths may have come in at least two shades, according to new genetic research.

Scientists have dug up several of the Pleistocene-era beasts in recent years, and a few well-preserved specimens have yielded remains of the animals' distinctive hairy coats. However, scientists weren't sure whether the color variations they've seen represent mammoths' true hues, notes evolutionary biologist Michael Hofreiter of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.

"No one knew whether differences in hair color came from genetic differences between animals or from storage in the soil for 10,000 years" says Hofreiter.

To investigate, he and his colleagues examined a gene called mc1r, isolated from the leg bone of a 43,000-year-old mammoth. A similar gene controls color in a variety of other animals, including people, mice, and chickens.

The researchers found distinct differences between the two copies of mc1r present in each mammoth-bone cell, suggesting that the gene existed in at least two forms with varying activity.

Previous research had shown that less active versions of mc1r are responsible for lighter hair color in mice and people. The less active gene variant probably led to lighter shades of woolly mammoths as well, the team reports in the July 7 Science.--C.B.