2021年经济学人 会唱歌的鸟儿爱吃糖(2)

To find out, they cloned T1R1-T1R3 receptors from a variety of songbirds and tested their responses to sugar.

为了找到答案，他们从各种鸣禽中克隆了T1R1-T1R3受体，并测试了它们对糖的反应。

All the receptors they tested—from birds with sugar-rich and sugar-poor diets alike—interacted strongly with sugar molecules¹.

他们测试的所有受体——来自高糖和低糖饮食的鸟类——都与糖分子发生了强烈的相互作用。

This confirmed that, as with hummingbirds², songbirds regained³ perception of sweetness via mutations of the gene⁴ for T1R1 and T1R3.

该研究证实，鸣禽和蜂鸟一样，通过T1R1和T1R3基因的突变重新获得了对甜味的感知。

By contrast, umami receptors cloned from the Tyranni, a sister group to the Passeri, did not interact with sugars, though they did so strongly with amino acids typical of meat.

相比之下，从霸鹟亚目(雀形目的姐妹群)克隆的鲜味受体不与糖相互作用，虽然他们对肉类中典型的氨基酸有着强烈的反应。

The mutations in the songbird lineage must thus have happened after the Passeri and Tyranni lines diverged⁵, but before the Passeri themselves began proliferating⁶ into their current variety.

因此，鸣禽谱系的突变一定发生在雀形目和霸鹟亚目品种的分化之后，而又在雀形目本身开始繁殖成目前的品种之前。

Intriguingly⁷, when Dr Toda and Dr Baldwin looked at the molecular⁸ modifications⁹ which allowed the T1R1-T1R3 receptors of hummingbirds and Passeri to detect sweetness, they found them to be completely different.

有趣的是，户田博士和鲍德温博士研究了使蜂鸟和雀形目的T1R1-T1R3受体感知甜味的分子修饰，结果发现它们是完全不同的。

Both, though, involved numerous changes to the underlying¹⁰ DNA¹¹, suggesting a strong evolutionary¹² pressure to optimise them.

然而，这两种方法都涉及到基础DNA的大量变化，这表明有强大的进化压力来优化它们。

This pressure was probably a consequence of competition to fill the new ecological¹³ niches¹⁴ opened up by an ability to recognise sweet things as both edible¹⁵ and nutritious¹⁶.

这种压力很可能是人类为了填补新的生态位而展开竞争的结果，这种生态位是人类识别甜味食物既可食用又有营养的能力所开启的。

And it was that which resulted in the Passeri's current diversity.

这也导致了雀形目的多样性。

How all this ties up with the mellifluous¹⁷ songs sung by many members of the group is unclear.

这一切与该群体许多成员所唱的优美歌曲有何联系尚不清楚，可能只是一个巧合。

It may just be a coincidence. But if so, for those who enjoy bird song, it is a fortunate one.

但如果是这样，对于那些喜欢鸟鸣的人来说，这是幸运的。

1 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

2 hummingbirds   

n.蜂鸟( hummingbird的名词复数 )

参考例句：

• Hummingbirds have discovered that nectar and pollen are very nutritious. 蜂鸟发现花蜜和花粉是很有营养的。
• Why do hummingbirds and gorillas both have backbones? 为什么蜂鸟和大猩猩都有脊骨？

3 regained   

复得( regain的过去式和过去分词 )； 赢回； 重回； 复至某地

参考例句：

• The majority of the people in the world have regained their liberty. 世界上大多数人已重获自由。
• She hesitated briefly but quickly regained her poise. 她犹豫片刻，但很快恢复了镇静。

4 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。

5 diverged   

分开( diverge的过去式和过去分词 )； 偏离； 分歧； 分道扬镳

参考例句：

• Who knows when we'll meet again? 不知几时咱们能再见面！
• At what time do you get up? 你几时起床？

6 proliferating   

激增( proliferate的现在分词 )； （迅速）繁殖； 增生； 扩散

参考例句：

• Computerized data bases are proliferating fast. 计算机化的数据库正在激增。
• Crown galls are cancerous growths composed of disorganized and proliferating plant cells. 冠瘿是无组织的正在不断增殖的植物细胞所组成的癌状物。

7 intriguingly   

参考例句：

• Intriguingly, she gave to the music a developed although oddly malleable personality. 最神奇的是，她的音乐具有成熟却又很奇怪地极富可塑性。 来自互联网
• Intriguingly, the patients brains were riddled with tangles, but not amyloid plaques. 有趣的是，患者的大脑中充满了各缠结，但并没有粉斑。 来自互联网

8 molecular   

adj.分子的；克分子的

参考例句：

• The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
• For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时，分子的碰撞就停止了。

9 modifications   

n.缓和( modification的名词复数 )；限制；更改；改变

参考例句：

• The engine was pulled apart for modifications and then reassembled. 发动机被拆开改型，然后再组装起来。 来自《简明英汉词典》
• The original plan had undergone fairly extensive modifications. 原计划已经作了相当大的修改。 来自《简明英汉词典》

10 underlying   

adj.在下面的，含蓄的，潜在的

参考例句：

• The underlying theme of the novel is very serious.小说隐含的主题是十分严肃的。
• This word has its underlying meaning.这个单词有它潜在的含义。

11 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

12 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

13 ecological   

adj.生态的，生态学的

参考例句：

• The region has been declared an ecological disaster zone.这个地区已经宣布为生态灾难区。
• Each animal has its ecological niche.每种动物都有自己的生态位.

14 niches   

壁龛( niche的名词复数 )； 合适的位置[工作等]； （产品的）商机； 生态位（一个生物所占据的生境的最小单位）

参考例句：

• Some larvae extend the galleries to form niches. 许多幼虫将坑道延伸扩大成壁龛。
• In his view differences in adaptation are insufficient to create niches commensurate in number and kind. 按照他的观点，适应的差异不足以在数量上和种类上形成同量的小生境。

15 edible   

n.食品，食物；adj.可食用的

参考例句：

• Edible wild herbs kept us from dying of starvation.我们靠着野菜才没被饿死。
• This kind of mushroom is edible,but that kind is not.这种蘑菇吃得，那种吃不得。

16 nutritious   

adj.有营养的，营养价值高的

参考例句：

• Fresh vegetables are very nutritious.新鲜蔬菜富于营养。
• Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。

17 mellifluous   

adj.（音乐等）柔美流畅的

参考例句：

• Soon the room is filled with Bates' mellifluous tones.很快，房间里便充满了贝茨动听的声音。
• Her voice was distinctive,soft and mellifluous.她的嗓音甜美，清脆而柔和。