万物简史 第579期:生命的物质(5)

That is why it can be recovered from patches of long-dried blood or semen in murder investigations¹ and coaxed² from the bones of ancient Neandertals. It also explains why it took scientists so long to work out how a substance so mystifyingly low key — so, in a word, lifeless — could be at the very heart of life itself.

这就是人们在谋杀案调查中能从干涸已久的血迹或精液中，以及能从古代尼安德特入骨骼中提取出DNA³的原因。这也解释了为什么科学家花了如此长的一段时间才破译出这样一种看似无关紧要的——一句话，没有生命的——神秘物质，在生命本身中却占据十分重要地位。

As a known entity⁴, DNA has been around longer than you might think. It was discovered as far back as 1869 by Johann Friedrich Miescher, a Swiss scientist working at the University of Tubingen in Germany. While delving⁵ microscopically⁶ through the pus in surgical⁷ bandages, Miescher found a substance he didn't recognize and called it nuclein (because it resided in the nuclei⁸ of cells). At the time, Miescher did little more than note its existence, but nuclein clearly remained on his mind, for twenty-three years later in a letter to his uncle he raised the possibility that such molecules⁹ could be the agents behind heredity. This was an extraordinary insight, but one so far in advance of the day's scientific requirements that it attracted no attention at all.

作为一种已知的实体，DNA存在的时间之长超乎你的想像。可是，直到1869年，DNA才由一位任职于德国蒂宾根大学的瑞士科学家约翰·弗里德里希·米歇尔发现。在通过显微镜研究外科手术绷带的脓液时，米歇尔发现了一种他不认识的物质，他给它取名为核素（因为它寄居在细胞核里）。当时米歇尔只注意到它的存在，但核素显然在他的心中留下了深刻印象。23年后，在给他叔叔的一封信中，米歇尔提出，这种分子可能是隐藏在遗传背后的原动力。这是一个极具洞察力的观点，但是这个观点超出了当时的科学要求，因此根本没有引起人们的注意。

For most of the next half century the common assumption was that the material — now called deoxyribonucleic acid, or DNA — had at most a subsidiary role in matters of heredity. It was too simple. It had just four basic components¹⁰, called nucleotides, which was like having an alphabet of just four letters. How could you possibly write the story of life with such a rudimentary alphabet? (The answer is that you do it in much the way that you create complex messages with the simple dots and dashes of Morse code — by combining them.)

在以后的半个世纪的大部分时间里，人们普遍认为，这种物质——现在被称为脱氧核糖核酸或DNA——在遗传中所扮演的充其量是一个微不足道的角色。它太简单了，主要由4个被称为核苷酸的基本物质组成。这就好比一个只有4个字母的字母表。你怎么可能用这区区4个字母编写生命的故事？（答案在很大程度上类同于你用莫尔斯电码的点和划——将它们串连起来——去写一封内容复杂的电报。）

1 investigations   

（正式的）调查( investigation的名词复数 )； 侦查； 科学研究； 学术研究

参考例句：

• His investigations were intensive and thorough but revealed nothing. 他进行了深入彻底的调查，但没有发现什么。
• He often sent them out to make investigations. 他常常派他们出去作调查。

2 coaxed   

v.哄，用好话劝说( coax的过去式和过去分词 )；巧言骗取；哄劝，劝诱

参考例句：

• She coaxed the horse into coming a little closer. 她哄着那匹马让它再靠近了一点。
• I coaxed my sister into taking me to the theatre. 我用好话哄姐姐带我去看戏。 来自《现代汉英综合大词典》

3 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。

4 entity   

n.实体，独立存在体，实际存在物

参考例句：

• The country is no longer one political entity.这个国家不再是一个统一的政治实体了。
• As a separate legal entity,the corporation must pay taxes.作为一个独立的法律实体，公司必须纳税。

5 delving   

v.深入探究，钻研( delve的现在分词 )

参考例句：

• He has been delving into the American literature of 20th century. 他一直在潜心研究美国20世纪文学。 来自互联网
• In some ways studying Beckett is like delving into Shakespeare's words. 在某些方面，研究Beckett的戯好像是深入研究莎士比亚的语句。 来自互联网

6 microscopically   

显微镜下

参考例句：

• Microscopically the ores are medium grained to amorphous. 显微镜下，矿石为中粒至非晶质。 来自辞典例句
• He studied microscopically the statistics of trade. 他极仔细地研究了贸易统计数字。 来自辞典例句

7 surgical   

adj.外科的，外科医生的，手术上的

参考例句：

• He performs the surgical operations at the Red Cross Hospital.他在红十字会医院做外科手术。
• All surgical instruments must be sterilised before use.所有的外科手术器械在使用之前，必须消毒。

8 nuclei   

n.核

参考例句：

• To free electrons, something has to make them whirl fast enough to break away from their nuclei. 为了释放电子，必须使电子高速旋转而足以摆脱原子核的束缚。
• Energy is released by the fission of atomic nuclei. 能量是由原子核分裂释放出来的。

9 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。

10 components   

（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分

参考例句：

• the components of a machine 机器部件
• Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。