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Endurance Gene

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.

Scientists believe our endurance running abilities began to appear two million 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.

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.

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

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.

参考译文

智人远非动物王国里跑得最快的,但速度的不足,有耐力来弥补。我们的一些生理特性,让我们善于长途奔袭:我们的臀部肌肉比其他灵长类更丰满,我们还退化了大部分皮毛,进化出许多汗腺,帮助我们降温。

科学家们认为,两三百万年前,大约在人属出现的时候,我们的耐跑能力开始出现。一项新的研究表明,这与一个关键基因的突变有关。

这种被称为 CMAH 基因的突变,改变了修饰我们身体每个细胞表面的糖分子的类型,这反过来可能使我们的肌肉不易疲劳。

研究人员现在发现,与普通老鼠相比,有这种基因变异的老鼠跑得更远,更不易疲惫。基因突变的老鼠在轮子上跑出的里程数更多,看来,这只老鼠跑得还挺开心。它们的后腿肌肉中有更多的毛细血管,可以增加耐力运动中营养素和氧气的输送。这项研究的完整统计数据发表在英国皇家学会学报生物学会刊上。

这种基因小突变会否给人类带来和老鼠一样的好处,目前尚不清楚。但如果真是这样,我们就很好解释早期人类何以捷足先登。

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