That is why it can be recovered from patches of long-dried blood or semen in murder investigations and coaxed 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.
這就是人們在謀殺案調查中能從干涸已久的血跡或精液中，以及能從古代尼安德特入骨骼中提取出DNA的原因。這也解釋了為什么科學家花了如此長的一段時間才破譯出這樣一種看似無關緊要的——一句話，沒有生命的——神秘物質，在生命本身中卻占據十分重要地位。
As a known entity, 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 delving microscopically through the pus in surgical bandages, Miescher found a substance he didn't recognize and called it nuclein (because it resided in the nuclei 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 molecules 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.
作為一種已知的實體，DNA存在的時間之長超乎你的想像。可是，直到1869年，DNA才由一位任職于德國蒂賓根大學的瑞士科學家約翰·弗里德里希·米歇爾發現。在通過顯微鏡研究外科手術繃帶的膿液時，米歇爾發現了一種他不認識的物質，他給它取名為核素（因為它寄居在細胞核里）。當時米歇爾只注意到它的存在，但核素顯然在他的心中留下了深刻印象。23年后，在給他叔叔的一封信中，米歇爾提出，這種分子可能是隱藏在遺傳背后的原動力。這是一個極具洞察力的觀點，但是這個觀點超出了當時的科學要求，因此根本沒有引起人們的注意。
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 components, 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.)
在以后的半個世紀的大部分時間里，人們普遍認為，這種物質——現在被稱為脫氧核糖核酸或DNA——在遺傳中所扮演的充其量是一個微不足道的角色。它太簡單了，主要由4個被稱為核苷酸的基本物質組成。這就好比一個只有4個字母的字母表。你怎么可能用這區區4個字母編寫生命的故事？（答案在很大程度上類同于你用莫爾斯電碼的點和劃——將它們串連起來——去寫一封內容復雜的電報。）
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