The same gene that gives redheads their fiery locks gave woolly mammoths either light or dark coats
Researchers made the discovery after sequencing a gene found in ancient DNA taken from the leg bone of a frozen Siberian mammoth.
The gene is known to help determine hair color in many mammals, from humans to mice.
The study marks the first time researchers have mapped a complete gene from the nuclear DNA of an extinct animal. It also explains the different shades found in preserved mammoth hair.
"Nobody knew if the hair changed its color over time lying in the soil, or whether there is a genetic basis for these color differences," said Michael Hofreiter, an evolutionary biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
His research suggests the latter, although scientists still don't know which color hair the Ice Age beasts grew, only that it came in light and dark shades.
More significantly, the breakthrough opens the door for similar genetic studies of mammoths and other extinct species from the not-too-distant past, such as cave bears and Neandertals.
"If you want to find characteristics of a species that don't fossilize — that you can't tell from the bones — we have to analyze these genes," Hofreiter said.
Mammoth blondes and really hairy brunettes
Gene reveals mammoth coat colour
I'm a natural brunette