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.
出生在约6000到1万年前的所有蓝眼睛的人，有一个共同的祖先。蓝眼睛是由基因变异造成的。多少年来，研究人员们一直在OCA2基因上寻找它。OCA2基因决定了你眼睛里有多少褐色素。然而他们要寻找的东西根本就不在这儿。
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.
这种突变是在一种完全不同的、叫做HERC2的基因上发现的。HERC2关闭了OCA2，也就是说它关闭了褐色素，只显示了蓝色。每个蓝眼睛的人都有这种变异。
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.
这种基因的变异是如何产生的？可能是人类在从非洲迁移到欧洲的过程中形成的。这就解释了为什么只有欧洲血统的人才有蓝眼睛。这也意味着所有蓝眼睛的人都有一个共同的欧洲祖先。
Now, that’s an impressive family tree!
现在，这个族谱是不是让你很吃惊！
