Unit 59
The basic workings of DNA and RNA are no mystery. It's now well known that DNA consists of four nucleotide "bases" （A, T, C and G）, whose linear sequences （AATAGGCTCC……） encode hereditary information. Genes——discrete segments of long DNA molecules——transcribe their sequences onto single-strand messenger RNA molecules, which then serve as templates for proteins. In short, DNA makes messenger RNA, and messenger RNA makes proteins. The production of a particular protein is the goal of each gene. This 50-year-old insight is the bedrock of modern biology, but science has not fully solved a related mystery. If every cell in an organism contains the same full complement of genes, why are the cells themselves so varied? How do different genes get turned on （"expressed"） or off （"silenced"） in just the right combinations to produce heart cells, bone cells and brain cells?
That's where microRNA enters the picture. In the early 1990s, researchers studying a species of worm discovered genes for a very short and very unusual piece of RNA. Instead of synthesizing proteins, this tiny RNA molecule latched onto messenger RNAs （chart）, causing their destruction. Without messenger RNA, no protein was produced. In effect, the gene for that protein had been silenced. The discovery was initially dismissed as an oddity in a worm, but scientists have since found genes for hundreds of microRNAs in various plants and animals——200 in humans alone. Many of these genes have survived in identical forms in different species, indicating that they are essential to life. What, exactly, is their role? We now suspect that by silencing particular genes at just the right times——a process called RNA interference——they push genetically identical cells down different paths of development, enabling some to digest food while others perceive light.
RNA interference gives researchers a new tool for understanding how living things grow——how a plant assumes a particular shape, for example, or how a baby's hand forms during gestation. Moreover, because microRNAs are so small and simple in structure, they can be manufactured for use as research tools. If scientists suspect that a particular gene is responsible for a disease, they can design microRNA to silence the gene in affected laboratory animals. If the disease is prevented or cured, the gene becomes a target for treatment.
RNA interference has yet to generate new medicines, but if the technique fulfills its promise, it could help us treat everything from viral infections to cancer. MicroRNAs could be used to seal off human cells from disease-causing viruses, or to disable viruses that gain entry. In a recent test-tube study, researchers showed that RNA interference could make cells impermeable to HIV. Early studies suggest that microRNAs can also boost the production of stem cells in culture. By blocking production of growth-promoting proteins, microRNAs may even help contain cancer cells.
It is one thing to manipulate cells in a test tube, quite another to treat people. Getting microRNAs safely into the right cells in the body will be complicated. No one has yet attempted a human experiment. Even so, a field that was just a curiosity in 1993 is now poised to change the world——all because we invested in basic research. The scientists who discovered microRNAs were not trying to prevent AIDS, grow stem cells or treat cancer. They just wanted to figure out how something happened in a worm. As Buckminster Fuller observed, "Development is programmable; discovery is not."
注（1）：本文選自Newsweek; 12/8/2003, p96-96, 1p, 1 diagram, 1c；
注（2）：本文習(xí)題命題模仿對象2004年真題Text 3；
1. The expression “silenced”（Line 5, Paragraph 2） most probably means _________.
[A]ruined
[B]destroyed
[C]killed
[D]stopped
2. How does the author feel about the study of MicroRNA?
[A]Optimistic.
[B]Confused.
[C]Frightening.
[D]Shocking.
3.When mentioning “It is one thing to manipulate cells in a test tube, quite another to treat people.“（Line 1, Paragraph 5）, the author implies that __________.
[A]the test of cells and the treatment of people are unrelated to each other
[B]the treatment of people is more complex than the cells in the laboratory
[C]more emphasis should be laid on the human tests
[D]human treatment may not be successful
3. What does Buckminster Fuller mean by “Development is programmable; discovery is not.“（Last Line, Last Paragraph）?
[A]Discovery is always made beyond one's expectation.
[B]Development is easier than discovery.
[C]Development lacks curiosity while discovery does not.
[D]Development is less important than discovery.
4.Which of the following is not true about RNA interference?
[A]It prevents disease-causing viruses from entering human body.
[B]It improves the production of stem cells.
[C]It can cure of all kinds of human diseases.
[D]It silences certain protein to prevent tumor.
答案：DABAC
篇章剖析
本文采用提出問題——分析問題的模式，指出小分子核糖核酸的發(fā)現(xiàn)、作用機理及其應(yīng)用。第一段指出脫氧核糖核酸、信使核糖核酸、蛋白質(zhì)之間的關(guān)系；第二段指出小分子核糖核酸的發(fā)現(xiàn)及其作用機理；第三段和第四段指出核糖核酸干擾的具體作用及其應(yīng)用；第五段指出這一發(fā)現(xiàn)的偶然性。
詞匯注釋
unravel[Qn5rAv（E）l]v.分散并澄清（神秘或讓人迷惑的事物）的構(gòu)成元素；解開
come to light v.暴露;被發(fā)現(xiàn),眾所周知
nucleotide[`njU:klIEtaId, -tId]n.核苷
encode[In5kEJd]vt.把（電文.情報等）譯成電碼（或密碼）；編碼
hereditary[hI5redItErI; （?@） -terI]adj.世襲的, 遺傳的
synthesize[5sInWIsaIz]v.綜合, 合成
gestation[dVe5steIF（E）n]n.懷孕, 醞釀, 妊娠
seal off v.把……封鎖起來
HIV abbr. 人體免疫缺損病毒，艾滋病病毒
impermeable[Im5p\:mIEb（E）l]adj.不能滲透的, 不滲透性的
manipulate[mE5nIpjJleIt]vt.（熟練地）操作,巧妙地處理
be poised to 準備好的
難句突破
We now suspect that by silencing particular genes at just the right times——a process called RNA interference——they push genetically identical cells down different paths of development, enabling some to digest food while others perceive light.
主體句式：We suspect that …
結(jié)構(gòu)分析：本句是一個賓語從句。介詞by做伴隨狀語，其中“a process called RNA interference”是“silencing particular genes at just the right times”的同位語；現(xiàn)在分詞“enabling”做伴隨狀語，其中連詞“while”表示對比。
句子譯文：我們現(xiàn)在猜測它們在某一適當?shù)臅r候通過壓制一些特殊的基因——這是一個被稱為核糖核酸干擾的過程——推動基因相同的細胞發(fā)展成不同的性狀，從而使一些細胞能夠消化食物，另一些細胞能夠感知光線。
題目分析
1.答案為D，屬猜詞題。從文章第一段“How do different genes get turned on （"expressed"） or off （"silenced"） in just the right combinations to produce heart cells, bone cells and brain cells?”我們可看出“silence”的意思是“turn off”。句子“Instead of synthesizing proteins, this tiny RNA molecule latched onto messenger RNAs （chart）, causing their destruction. Without messenger RNA, no protein was produced. In effect, the gene for that protein had been silenced.”的意思是“這種小核糖核酸分子沒有參與合成蛋白質(zhì)，而是附著在信使核糖核酸上（如圖），來消滅它們。沒有信使核糖核酸，也就產(chǎn)生不了蛋白質(zhì)。實際上，產(chǎn)生這種蛋白質(zhì)的基因被壓制了。”，從這句話我們可進一步了解“turn off”到底是什么含義。
2.答案為A，屬情感態(tài)度題。雖然“It is one thing to manipulate cells in a test tube, quite another to treat people.”，但是從句子“RNA interference has yet to generate new medicines, but if the technique fulfills its promise, it could help us treat everything from viral infections to cancer.”和“Even so, a field that was just a curiosity in 1993 is now poised to change the world——all because we invested in basic research.”我們可看出作者對小核糖核酸分子前景是非?？春玫摹?BR> 3.答案為B，屬推理判斷題。文章第四段闡述了小核糖核酸分子的應(yīng)用前景是非常好的，但那都是在實驗室里做出來的，還沒有具體應(yīng)用到人體上。應(yīng)用到人體上又是另一回事，要復(fù)雜的多了。
4.答案為A，屬推理判斷題。文章最后一段談及了小核糖核酸分子是意外發(fā)現(xiàn)的，是“無心插柳”的意外收獲和發(fā)現(xiàn)?！癉evelopment is programmable; discovery is not.”是對這一事實的一個很好的概括。
5.答案為C，屬事實細節(jié)題。原文對應(yīng)信息是：“No one has yet attempted a human experiment.” .
參考譯文
脫氧核糖核酸（DNA）和核糖核酸（RNA）的基本運行方式并不是不解之迷?，F(xiàn)在大家都知道脫氧核糖核酸是由堿基（A, T, C and G）構(gòu)成的。堿基通過線形排列（AATAGGCTCC……）對遺傳信息進行編碼?；颉L長的脫氧核糖核酸分子中的不連續(xù)的片段——把它們的序列轉(zhuǎn)錄成單線信使核糖核酸分子，核糖核酸又成為蛋白質(zhì)的模板。簡言之，脫氧核糖核酸產(chǎn)生了信使核糖核酸，信使核糖核酸又產(chǎn)生了蛋白質(zhì)。產(chǎn)生一種獨特的蛋白質(zhì)是每一個基因的目標。這種認識已長達50年，它是現(xiàn)代生物學(xué)的基礎(chǔ)。但是科學(xué)并沒有完全解決一個相關(guān)的問題。如果生物體內(nèi)的每一個細胞都含有同等滿額的基因的話，那么為什么細胞之間千差萬別呢？不同的基因是如何以適當?shù)慕M合方式來開始（表達）或停止（沉默）自己的工作，從而制造心臟、骨骼以及腦部細胞呢？
于是小分子核糖核酸（microRNA）進入了我們的視野。在20世紀90年代初，研究人員在研究一種蟲子的基因時發(fā)現(xiàn)了一種很短卻又與眾不同的核糖核酸。這種小核糖核酸分子沒有參與合成蛋白質(zhì)，而是附著在信使核糖核酸上（如圖），來消滅它們。沒有信使核糖核酸，也就產(chǎn)生不了蛋白質(zhì)。實際上，產(chǎn)生這種蛋白質(zhì)的基因被壓制了。這一發(fā)現(xiàn)剛開始時被認為是蟲子體內(nèi)的奇怪物質(zhì)而未被考慮，但后來科學(xué)家們在各種動植物身上發(fā)現(xiàn)了成百上千個小分子核糖核酸基因——單在人身上就發(fā)現(xiàn)了200個。有很多這樣的基因以相同的形態(tài)存活在不同的物種體內(nèi)，這表明它們對生命來說是必不可少的。那么它們究竟起什么作用呢？我們現(xiàn)在猜測它們在某一適當?shù)臅r候通過壓制一些特殊的基因——這是一個被稱為核糖核酸干擾的過程——推動基因相同的細胞發(fā)展成不同的性狀，從而使一些細胞能夠消化食物，另一些細胞能夠感知光線。
核糖核酸的干擾作用為研究人員搞清生命生長提供了一個新工具——比如說，植物是如何展現(xiàn)其獨特外形的，嬰兒的小手在母體里是如何形成的，等等。此外，因為小分子核糖核酸的構(gòu)造既小又簡單，所以可以制造核糖核酸，把它當作研究工具來使用。如果科學(xué)家們懷疑某種疾病是由于某一種基因出了問題，那么他們可以設(shè)計小分子核糖核酸，用以壓制實驗室里受感染的動物體內(nèi)的基因。如果這種疾病得以預(yù)防或治愈，那么這種基因便成為了治療的對象。
核糖核酸干擾可以用來生產(chǎn)新藥。如果科技確實能起作用，它就可以幫助我們治療從病毒感染到癌癥等各種疾病。小分子核糖核酸可以用來封閉人體細胞，使之免受致病病毒的侵擾，或者使病毒喪失侵入細胞的能力。在最近進行的試管實驗研究中，研究人員發(fā)現(xiàn)核糖核酸干擾能使細胞抵制愛滋病病毒。早期研究發(fā)現(xiàn)小分子核糖核酸還可以促進干細胞的產(chǎn)生。通過阻止那些能促進生長發(fā)育的蛋白質(zhì)的產(chǎn)生，小分子核糖核酸甚至還能有助于抑制癌細胞。
用試管做細胞實驗是一回事，用于人身上又是另一回事了。使小分子核糖核酸安全進入適合的細胞體內(nèi)是一項復(fù)雜的過程。至今還無人嘗試人體實驗。盡管這樣，這個在1993年還是件新奇事物的領(lǐng)域現(xiàn)在將要改變世界——這都是因為我們花精力進行了基礎(chǔ)研究。那些發(fā)現(xiàn)小分子核糖核酸的科學(xué)家們并沒想要去防治愛滋病、種植干細胞或者治療癌癥。他們只想搞明白蟲子體內(nèi)究竟發(fā)生了什么。正如匹克米斯特·福勒評述的：“開發(fā)項目有程序可循，而發(fā)現(xiàn)卻非如此了。”
The basic workings of DNA and RNA are no mystery. It's now well known that DNA consists of four nucleotide "bases" （A, T, C and G）, whose linear sequences （AATAGGCTCC……） encode hereditary information. Genes——discrete segments of long DNA molecules——transcribe their sequences onto single-strand messenger RNA molecules, which then serve as templates for proteins. In short, DNA makes messenger RNA, and messenger RNA makes proteins. The production of a particular protein is the goal of each gene. This 50-year-old insight is the bedrock of modern biology, but science has not fully solved a related mystery. If every cell in an organism contains the same full complement of genes, why are the cells themselves so varied? How do different genes get turned on （"expressed"） or off （"silenced"） in just the right combinations to produce heart cells, bone cells and brain cells?
That's where microRNA enters the picture. In the early 1990s, researchers studying a species of worm discovered genes for a very short and very unusual piece of RNA. Instead of synthesizing proteins, this tiny RNA molecule latched onto messenger RNAs （chart）, causing their destruction. Without messenger RNA, no protein was produced. In effect, the gene for that protein had been silenced. The discovery was initially dismissed as an oddity in a worm, but scientists have since found genes for hundreds of microRNAs in various plants and animals——200 in humans alone. Many of these genes have survived in identical forms in different species, indicating that they are essential to life. What, exactly, is their role? We now suspect that by silencing particular genes at just the right times——a process called RNA interference——they push genetically identical cells down different paths of development, enabling some to digest food while others perceive light.
RNA interference gives researchers a new tool for understanding how living things grow——how a plant assumes a particular shape, for example, or how a baby's hand forms during gestation. Moreover, because microRNAs are so small and simple in structure, they can be manufactured for use as research tools. If scientists suspect that a particular gene is responsible for a disease, they can design microRNA to silence the gene in affected laboratory animals. If the disease is prevented or cured, the gene becomes a target for treatment.
RNA interference has yet to generate new medicines, but if the technique fulfills its promise, it could help us treat everything from viral infections to cancer. MicroRNAs could be used to seal off human cells from disease-causing viruses, or to disable viruses that gain entry. In a recent test-tube study, researchers showed that RNA interference could make cells impermeable to HIV. Early studies suggest that microRNAs can also boost the production of stem cells in culture. By blocking production of growth-promoting proteins, microRNAs may even help contain cancer cells.
It is one thing to manipulate cells in a test tube, quite another to treat people. Getting microRNAs safely into the right cells in the body will be complicated. No one has yet attempted a human experiment. Even so, a field that was just a curiosity in 1993 is now poised to change the world——all because we invested in basic research. The scientists who discovered microRNAs were not trying to prevent AIDS, grow stem cells or treat cancer. They just wanted to figure out how something happened in a worm. As Buckminster Fuller observed, "Development is programmable; discovery is not."
注（1）：本文選自Newsweek; 12/8/2003, p96-96, 1p, 1 diagram, 1c；
注（2）：本文習(xí)題命題模仿對象2004年真題Text 3；
1. The expression “silenced”（Line 5, Paragraph 2） most probably means _________.
[A]ruined
[B]destroyed
[C]killed
[D]stopped
2. How does the author feel about the study of MicroRNA?
[A]Optimistic.
[B]Confused.
[C]Frightening.
[D]Shocking.
3.When mentioning “It is one thing to manipulate cells in a test tube, quite another to treat people.“（Line 1, Paragraph 5）, the author implies that __________.
[A]the test of cells and the treatment of people are unrelated to each other
[B]the treatment of people is more complex than the cells in the laboratory
[C]more emphasis should be laid on the human tests
[D]human treatment may not be successful
3. What does Buckminster Fuller mean by “Development is programmable; discovery is not.“（Last Line, Last Paragraph）?
[A]Discovery is always made beyond one's expectation.
[B]Development is easier than discovery.
[C]Development lacks curiosity while discovery does not.
[D]Development is less important than discovery.
4.Which of the following is not true about RNA interference?
[A]It prevents disease-causing viruses from entering human body.
[B]It improves the production of stem cells.
[C]It can cure of all kinds of human diseases.
[D]It silences certain protein to prevent tumor.
答案：DABAC
篇章剖析
本文采用提出問題——分析問題的模式，指出小分子核糖核酸的發(fā)現(xiàn)、作用機理及其應(yīng)用。第一段指出脫氧核糖核酸、信使核糖核酸、蛋白質(zhì)之間的關(guān)系；第二段指出小分子核糖核酸的發(fā)現(xiàn)及其作用機理；第三段和第四段指出核糖核酸干擾的具體作用及其應(yīng)用；第五段指出這一發(fā)現(xiàn)的偶然性。
詞匯注釋
unravel[Qn5rAv（E）l]v.分散并澄清（神秘或讓人迷惑的事物）的構(gòu)成元素；解開
come to light v.暴露;被發(fā)現(xiàn),眾所周知
nucleotide[`njU:klIEtaId, -tId]n.核苷
encode[In5kEJd]vt.把（電文.情報等）譯成電碼（或密碼）；編碼
hereditary[hI5redItErI; （?@） -terI]adj.世襲的, 遺傳的
synthesize[5sInWIsaIz]v.綜合, 合成
gestation[dVe5steIF（E）n]n.懷孕, 醞釀, 妊娠
seal off v.把……封鎖起來
HIV abbr. 人體免疫缺損病毒，艾滋病病毒
impermeable[Im5p\:mIEb（E）l]adj.不能滲透的, 不滲透性的
manipulate[mE5nIpjJleIt]vt.（熟練地）操作,巧妙地處理
be poised to 準備好的
難句突破
We now suspect that by silencing particular genes at just the right times——a process called RNA interference——they push genetically identical cells down different paths of development, enabling some to digest food while others perceive light.
主體句式：We suspect that …
結(jié)構(gòu)分析：本句是一個賓語從句。介詞by做伴隨狀語，其中“a process called RNA interference”是“silencing particular genes at just the right times”的同位語；現(xiàn)在分詞“enabling”做伴隨狀語，其中連詞“while”表示對比。
句子譯文：我們現(xiàn)在猜測它們在某一適當?shù)臅r候通過壓制一些特殊的基因——這是一個被稱為核糖核酸干擾的過程——推動基因相同的細胞發(fā)展成不同的性狀，從而使一些細胞能夠消化食物，另一些細胞能夠感知光線。
題目分析
1.答案為D，屬猜詞題。從文章第一段“How do different genes get turned on （"expressed"） or off （"silenced"） in just the right combinations to produce heart cells, bone cells and brain cells?”我們可看出“silence”的意思是“turn off”。句子“Instead of synthesizing proteins, this tiny RNA molecule latched onto messenger RNAs （chart）, causing their destruction. Without messenger RNA, no protein was produced. In effect, the gene for that protein had been silenced.”的意思是“這種小核糖核酸分子沒有參與合成蛋白質(zhì)，而是附著在信使核糖核酸上（如圖），來消滅它們。沒有信使核糖核酸，也就產(chǎn)生不了蛋白質(zhì)。實際上，產(chǎn)生這種蛋白質(zhì)的基因被壓制了。”，從這句話我們可進一步了解“turn off”到底是什么含義。
2.答案為A，屬情感態(tài)度題。雖然“It is one thing to manipulate cells in a test tube, quite another to treat people.”，但是從句子“RNA interference has yet to generate new medicines, but if the technique fulfills its promise, it could help us treat everything from viral infections to cancer.”和“Even so, a field that was just a curiosity in 1993 is now poised to change the world——all because we invested in basic research.”我們可看出作者對小核糖核酸分子前景是非?？春玫摹?BR> 3.答案為B，屬推理判斷題。文章第四段闡述了小核糖核酸分子的應(yīng)用前景是非常好的，但那都是在實驗室里做出來的，還沒有具體應(yīng)用到人體上。應(yīng)用到人體上又是另一回事，要復(fù)雜的多了。
4.答案為A，屬推理判斷題。文章最后一段談及了小核糖核酸分子是意外發(fā)現(xiàn)的，是“無心插柳”的意外收獲和發(fā)現(xiàn)?！癉evelopment is programmable; discovery is not.”是對這一事實的一個很好的概括。
5.答案為C，屬事實細節(jié)題。原文對應(yīng)信息是：“No one has yet attempted a human experiment.” .
參考譯文
脫氧核糖核酸（DNA）和核糖核酸（RNA）的基本運行方式并不是不解之迷?，F(xiàn)在大家都知道脫氧核糖核酸是由堿基（A, T, C and G）構(gòu)成的。堿基通過線形排列（AATAGGCTCC……）對遺傳信息進行編碼?；颉L長的脫氧核糖核酸分子中的不連續(xù)的片段——把它們的序列轉(zhuǎn)錄成單線信使核糖核酸分子，核糖核酸又成為蛋白質(zhì)的模板。簡言之，脫氧核糖核酸產(chǎn)生了信使核糖核酸，信使核糖核酸又產(chǎn)生了蛋白質(zhì)。產(chǎn)生一種獨特的蛋白質(zhì)是每一個基因的目標。這種認識已長達50年，它是現(xiàn)代生物學(xué)的基礎(chǔ)。但是科學(xué)并沒有完全解決一個相關(guān)的問題。如果生物體內(nèi)的每一個細胞都含有同等滿額的基因的話，那么為什么細胞之間千差萬別呢？不同的基因是如何以適當?shù)慕M合方式來開始（表達）或停止（沉默）自己的工作，從而制造心臟、骨骼以及腦部細胞呢？
于是小分子核糖核酸（microRNA）進入了我們的視野。在20世紀90年代初，研究人員在研究一種蟲子的基因時發(fā)現(xiàn)了一種很短卻又與眾不同的核糖核酸。這種小核糖核酸分子沒有參與合成蛋白質(zhì)，而是附著在信使核糖核酸上（如圖），來消滅它們。沒有信使核糖核酸，也就產(chǎn)生不了蛋白質(zhì)。實際上，產(chǎn)生這種蛋白質(zhì)的基因被壓制了。這一發(fā)現(xiàn)剛開始時被認為是蟲子體內(nèi)的奇怪物質(zhì)而未被考慮，但后來科學(xué)家們在各種動植物身上發(fā)現(xiàn)了成百上千個小分子核糖核酸基因——單在人身上就發(fā)現(xiàn)了200個。有很多這樣的基因以相同的形態(tài)存活在不同的物種體內(nèi)，這表明它們對生命來說是必不可少的。那么它們究竟起什么作用呢？我們現(xiàn)在猜測它們在某一適當?shù)臅r候通過壓制一些特殊的基因——這是一個被稱為核糖核酸干擾的過程——推動基因相同的細胞發(fā)展成不同的性狀，從而使一些細胞能夠消化食物，另一些細胞能夠感知光線。
核糖核酸的干擾作用為研究人員搞清生命生長提供了一個新工具——比如說，植物是如何展現(xiàn)其獨特外形的，嬰兒的小手在母體里是如何形成的，等等。此外，因為小分子核糖核酸的構(gòu)造既小又簡單，所以可以制造核糖核酸，把它當作研究工具來使用。如果科學(xué)家們懷疑某種疾病是由于某一種基因出了問題，那么他們可以設(shè)計小分子核糖核酸，用以壓制實驗室里受感染的動物體內(nèi)的基因。如果這種疾病得以預(yù)防或治愈，那么這種基因便成為了治療的對象。
核糖核酸干擾可以用來生產(chǎn)新藥。如果科技確實能起作用，它就可以幫助我們治療從病毒感染到癌癥等各種疾病。小分子核糖核酸可以用來封閉人體細胞，使之免受致病病毒的侵擾，或者使病毒喪失侵入細胞的能力。在最近進行的試管實驗研究中，研究人員發(fā)現(xiàn)核糖核酸干擾能使細胞抵制愛滋病病毒。早期研究發(fā)現(xiàn)小分子核糖核酸還可以促進干細胞的產(chǎn)生。通過阻止那些能促進生長發(fā)育的蛋白質(zhì)的產(chǎn)生，小分子核糖核酸甚至還能有助于抑制癌細胞。
用試管做細胞實驗是一回事，用于人身上又是另一回事了。使小分子核糖核酸安全進入適合的細胞體內(nèi)是一項復(fù)雜的過程。至今還無人嘗試人體實驗。盡管這樣，這個在1993年還是件新奇事物的領(lǐng)域現(xiàn)在將要改變世界——這都是因為我們花精力進行了基礎(chǔ)研究。那些發(fā)現(xiàn)小分子核糖核酸的科學(xué)家們并沒想要去防治愛滋病、種植干細胞或者治療癌癥。他們只想搞明白蟲子體內(nèi)究竟發(fā)生了什么。正如匹克米斯特·福勒評述的：“開發(fā)項目有程序可循，而發(fā)現(xiàn)卻非如此了。”