科学美国人60秒 SSS 基因突变使早期人类获得优势（在线收听）

This is Scientific American — 60-Second Science. I'm Christopher Intagliata.

这里是科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。

Homo sapiens are nowhere near the fastest runners in the animal kingdom. But what we lack in speed, we make up for in endurance. And we're specially equipped to go the distance. We've got bigger butt muscles than other primates. We lost most of our fur, too, and sprouted lots of sweat glands, to help us cool off.

智人的速度远不及动物界跑得最快的动物。但我们的耐力优势弥补了我们在速度上的不足。而且我们还拥有特殊的“装备”帮助我们跑长跑。我们的臀肌比其它灵长类动物要大。我们还褪去了大部分皮毛，长出大量汗腺帮助我们降温。

Scientists believe our endurance running abilities began to appear two to three million years ago, around the time the genus homo came about. And a new study suggests that a mutation in one key gene had something to do with it.

科学家认为我们的耐力跑能力在200万到300万年前开始产生，大约是人属出现前后。一项新研究发现，一个关键基因的突变与此有关。

The mutation, in what's called the CMAH gene, altered the types of sugar molecules that decorate the surfaces of every cell in our bodies. Which in turn may have made our muscles less prone to fatigue.

这种被称为CMAH基因的突变，改变了附着在我们体内每个细胞表面的糖分子的类型。这反过来可能令我们的肌肉不易疲劳。

Researchers have now found that mice bred with that same mutation can run longer without tiring, compared to regular mice. The mice with the gene alteration also logged more miles running on their wheels, apparently for fun. And they had more capillaries in their back leg muscles—which would increase the delivery of nutrients and oxygen during endurance exercise.

研究人员现在发现，与普通小鼠相比，基因突变的小鼠能跑得更久而不累。基因突变的小鼠还在轮子上跑了更多距离，这显然是为了好玩。它们的后腿肌肉中有更多毛细血管，这会在耐力训练中增加营养和氧气的输送。

The complete stats are in the Proceedings of the Royal Society B.

这项研究的完整统计数据刊登在《英国皇家学会学报：B辑》上。

It's unclear if this small genetic tweak endows humans with the same benefits as the mice. But if it does, it could help explain how early humans got a leg up on their competitors. Or, really, two legs.

目前并不清楚这种微小的基因变异是否能使人类获得与小鼠一样的好处。但是如果可以，那将有助于解释早期人类是如何在竞争中占据优势的。或者，实际上是获得了压倒性的优势。

Thanks for listening for Scientific American — 60-Second Science. I'm Christopher Intagliata.

谢谢大家收听科学美国人——60秒科学。我是克里斯托弗·因塔利亚塔。