The man's skeleton, along with that of a male companion, was discovered in 2006 in a cave in what is now northeastern Spain. The site, known as La Brana­Arintero, sits about 5,000 feet above sea level, and the cave provided a cold, refrigerator­like environment that preserved his DNA.

　　In the lab, scientists were able to remove enough DNA from a single tooth to reconstruct La Brana Ⅰ's entire genome (基因组).

　　They compared it to the DNA of other ancient Europeans (including Otzi, the 5,300­year­old mummy found in an Alpine glacier) and determined that he was a closer match with hunter­gatherers than with farmers.

　　When it came to genes that would influence La Brana Ⅰ's appearance, the researchers found that their 7,000­year­old subject had versions of two skin pigment (色素) genes that are either very rare or non－existent among Europeans today. Then they looked at other places in the genome that influence pigmentation (色素沉着) and found a mix of ancient and modern gene variants (变种). Taken together, La Brana Ⅰ's DNA “is likely to have resulted in dark skin pigmentation and dark or brown hair，” they wrote.

　　However, his DNA indicates that his eyes were most likely blue, the scientists found. This suggests that gene variants for light­colored eyes and skin did not spread together, they wrote, adding that La Brana Ⅰ's combination “of dark skin and non­brown eyes is unique and no longer present in contemporary European populations.” Today, a blue­eyed person would typically have fair skin.

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