字神帝國英語天地

☀ 今日主題：Most Tibetans Genetically Adapted to the High Life
大多數藏族人的基因決定: 他們適合住高地

☀ 洪欣老師推薦：托福聽力最好的課外教材：60-Second Science
☀ 康康精選托福會考的主題，堅持每天精聽一定會進步的哦!!

☀ 建議方法：
1. 先聽兩三遍 (不看文稿)
2. 再一句一句聽寫 (每句都要聽寫數遍，直到寫出85%以上的字)
3. 最後check文稿，看哪聽不出來，單字沒背過，還是發音不熟。
4. 堅持天天聽，就能每天進步哦。

☀ MP3音檔 (按右鍵可下載聽)：喜歡的同學，幫忙推或按讚哦~~
http://online1.tingclass.net/voaspe/…/20140914sa_science.mp3

☀ 只有音檔怎夠，聽不懂地方，不用怕，康康幫你準備好中英文稿了：

☀ 中英文稿：
When you hear the word 「mutation,」 you may think of something destructive, or of Marvel's X-Men. But some mutations—which are just differences in DNA—can be historic. Take, for example, a genetic sequence found in the vast majority of people from Tibet.
當你聽到「突變」這個詞，你可能會想到一些破壞性的東西，或漫威漫畫公司出品的X戰警。但是一些突變，如基因方面的差異，卻是有歷史意義的。舉個例子，就拿一組基因序列來說吧，該組基因序列存在於絕大多數的西藏居民中。

Millions of Tibetans spend their days at average elevations of nearly 15,000 feet—that's more than half the height of Mount Everest. Up there, the air is thin—with 40 percent less oxygen than at sea level. That lack of O2 would leave most Westerners struggling for breath, but Tibetans seem to breathe easy.
數以百萬計的藏族人居住在平均海拔近15000英呎的地方，這是一半珠穆朗瑪峰的高度。在西藏地區，空氣很稀薄，氧含量比海平面低40%，由於氧氣缺乏，大多數來到此地的西方人都會感覺到呼吸困難，但是藏族人卻不會。

To find out how these highlanders cope, researchers compared the DNA of 90 Tibetans to that of people who are not altitude adapted. And they discovered a single change that prevents Tibetans' blood from becoming dangerously clogged with red blood cells—a response that can be deadly for non-native mountaineers. The finding is described in the journal Nature Genetics. [Felipe R Lorenzo et al.: A genetic mechanism for Tibetan high-altitude adaptation]
為了弄明白這些藏族人如何做到的，研究人員將90名藏族人的DNA和對高原不適應的人的DNA進行了比較，研究人員發現：藏族居民的DNA中存在一個突 變，該突變可以防止藏族居民的血液被過多的紅細胞危險的堵塞。這種堵塞對非本地的登山者來說是致命的。這一發現被發表在《自然遺傳學》雜誌上。

This mutation appears to have originated just 8,000 years ago. But it's so advantageous that today nearly 90 percent of Tibetans have it. While it's virtually absent in even closely related lowland neighbors.
這種突變似乎起源於8000年前，但是如今，90%的藏族居民都存在這種突變，這對藏族人來說真是太有利了。但那些與高地居民聯繫緊密的低地居民卻幾乎沒有。
The finding demonstrates that a really useful mutation will always rise to the top.
— Karen Hopkin
這一發現表明，真正有用的突變總是能備受矚目。——凱倫‧霍普金