双语阅读英语外刊精讲:蓝眼睛的人拥有共同祖先

2019-05-02 09:01:00来源:酷学英语

  酷学英语全文通读

  All blue-eyed people have one ancestor in common, born around 6,000 to 10,000 years ago. Blue eyes are caused by a gene mutation. For years, researchers had searched for it on the OCA2 gene. The OCA2 gene determines how much brown pigment is in our eyes. But what they were looking for wasn’t there at all.

  The mutation was found on an entirely different gene called HERC2. HERC2 turns off OCA2, meaning it turns off the brown and reveals the blue. Every blue-eyed person has this exact same mutation.

  How did this mutation get its start? Possibly when humans migrated from Africa to Europe. This would explain why only people of European descent have blue eyes. It would also suggest that all blue-eyed people share a single European ancestor.

  Now, that’s an impressive family tree!

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