是什么让猛犸象熬过冰河时期？(双语有声)
作者：hahaleaf
来源：沪江论坛
2010-05-12 10:41
Evolved Blood Allowed Mammoths to Survive the Ice Age
A couple million years ago, mammoths migrated north from Africa to colonize Eurasia. Sometime around then a massive ice age kicked in—and it was stay warm or die. So their tails and heat-shedding ears shrunk, and they grew thick coats of oily fur.
数百万年前，猛犸象从非洲出发，进军欧亚大陆。就在那时，冰河时期来临了，在那种情况下，猛犸象要么想办法保暖，要么就只有冻死的份儿了。为适应环境，它们的尾巴和用来散热的大耳朵退化了，毛皮则变得又厚又多脂。
But if you're out in the cold all day you also need some biochemical adjustments. Hemoglobin is the protein in red blood cells that delivers oxygen to your tissues. And it doesn't off-load oxygen well at low temperatures; it just clings to it more tightly. So mammoths solved that problem by evolving hemoglobin that releases oxygen more easily in the cold. That’s according to a study published in the journal Nature Genetics.
你要是整天呆在寒冷的环境中，也会需要点生化调节。血红蛋白是人体内负责输送氧气的红细胞中的蛋白质。但是，在低温环境下，血红蛋白与氧黏着越发紧密，因此不能很好地卸载氧。当初，猛犸象是如何这一难题的呢？它们的血红蛋白进化了——变得更容易在寒冷环境中卸载氧。（参见《自然-遗传学》）
Researchers got the DNA that codes for hemoglobin from a 43,000-year-old mammoth specimen. They then used E. coli bacteria to produce actual mammoth hemoglobin. Then they compared mammoth hemoglobin to that of their living cousins, Asian elephants, at 37, 25 and 10 degrees Celsius. Due to just a few key structural changes, mammoth hemoglobin can release oxygen more readily at cold temperatures. Which was just the thing to help mammoths keep their cool.
研究人员从一头43000岁的猛犸象标本中获取了其血红蛋白DNA，然后用大肠杆菌培养新的血红蛋白。之后又将该血红蛋白和与它们形似的亚洲象的血红蛋白作对比，观察它们在37℃、25℃和10℃环境条件下的差异。结果发现，正是由于一些关键的构造性变异，猛犸象的血红蛋白能够更好地在低温环境下卸载氧，借此，猛犸象得以在冰河时期潇洒生存~
声明：音视频均来自互联网链接，仅供学习使用。本网站自身不存储、控制、修改被链接的内容。"沪江英语"高度重视知识产权保护。当如发现本网站发布的信息包含有侵犯其著作权的链接内容时，请联系我们，我们将依法采取措施移除相关内容或屏蔽相关链接。
沪江网校夏季课程上线，足不出户，和沪江网校一起天天向上，共同进步吧！
- 相关热点：
- 英语六级听力原文
