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Anyone who has vacationed in the higher elevations of Colorado, such as Vail and Estes Park, will tell you altitude sickness can be a real problem.
任何在科羅拉多的高海拔地區(qū)如韋爾和洛杉磯國家公園等旅游勝地度過假的人都會告訴你，高原反應(yīng)真的是要命的問題。
Loss of appetite, nausea, vomiting, weakness, dizziness, and difficulty sleeping can plague those visiting areas over eight thousand feet.
食欲不振，惡心，嘔吐，身體虛弱，頭暈，入睡困難等癥狀可能折磨那些在海拔超過8000英尺區(qū)域旅游的人們。
Altitude sickness results from the lack of oxygen at high elevations.
由于海拔較高而缺氧造成高原反應(yīng)。
At thirteen thousand feet, every lungful of air holds only sixty percent of what it would at sea level.
在13000英尺高的地方，肺僅能容納海平面高度時60%的空氣。
Despite that fact, many indigenous people live in areas of low oxygen concentration with few adverse effects.
盡管如此，許多在低氧地區(qū)的原居民很少有不良反應(yīng)。
The big question is, how do they survive?
那么值得我們思考的是，他們是怎樣存活的呢？
The body can adapt to low oxygen levels by making more hemoglobin, an oxygen-carrying molecule in red blood cells.
在氧氣稀薄的情況下，身體能夠產(chǎn)生一種適應(yīng)環(huán)境的血紅蛋白，這種血紅蛋白即是紅細(xì)胞的氧氣載體。
But too much hemoglobin over a long period of time can put a person at risk of blood clots, stroke, or chronic mountain sickness.
但是太多的血紅蛋白長時間存在可能導(dǎo)致人體產(chǎn)生血液凝塊，患上中風(fēng)或者患慢性高原病。
Scientists wondered how mountain people can remain healthy living at high altitudes.
科學(xué)家想知道在高原生活的人們怎樣維持健康。
To see if genes contribute, scientists analyzed the genomes of three ethnic groups living at altitudes over twelve thousand feet, two from Ethiopia, and Tibetans.
科學(xué)家們?yōu)榱俗C實(shí)基因是否有關(guān)，他們對3組生活在超過12000 英尺區(qū)域種族群體做了染色體分析，其中有兩組人來自埃塞俄比亞，另外一組來自西藏。
One Ethiopian group, the Oromo, cope the same way lowlanders do, by making more hemoglobin.
其中一組的埃塞俄比亞奧羅莫人與其他地方人一樣，他們的身體產(chǎn)生更多的血紅蛋白抵抗低氧環(huán)境。
The Amhara and Tibetans, on the other hand, have hemoglobin levels ten percent lower than the Oromo.
阿姆哈拉人和西藏人的血紅蛋白含量比奧羅莫人低10%左右。
Does genetic variation account for this?
是基因變異導(dǎo)致這種情況嗎？
Scientists found that both the Amhara and Tibetan highlanders possessed genetic variants associated with low hemoglobin levels.
科學(xué)家發(fā)現(xiàn)阿姆哈拉人和西藏人都有基因變異以維持低血紅蛋白水平。
But they were not the same genes.
但是他們的基因卻不同。
It appears that each group took a different evolutionary path to achieve the same outcome of dampening the usual response of increased hemoglobin.
看起來他們走了不同的進(jìn)化歷程，卻達(dá)到了相同的結(jié)果，那就是抑制人體在患高空癥時血紅蛋白的增長。
How about all those vacationers in Colorado?
在科羅拉多度假的人們怎么辦呢？
They will have to make do with their own lowland genes, for now.
目前只能用他們的低地基因來勉強(qiáng)應(yīng)付了。
