经济学人310:表观遗传学与健康 祖母的诅咒

 　　Science and technology

　　科学技术

　　Epigenetics and health

　　表观遗传学与健康

　　Grandma's curse

　　祖母的诅咒

　　Some of the effects of smoking may be passed from grandmother to grandchild

　　祖母吸烟产生的影响可以会遗传至孙子或孙女

　　Think of your grandchildren!

　　想想你的孙辈吧！

　　ONE of biology's hottest topics is epigenetics.

　　当今生物学最热的话题之一是表观遗传学，

　　The term itself covers a multitude of sins.

　　这个术语本身就涵盖了许多宗罪。

　　Strictly² speaking, it refers to the regulation of gene¹ expression by the chemical modification³ of DNA⁴, or of the histone proteins in which DNA is usually wrapped.

　　严格来说，表观遗传学研究的是DNA或含有DNA的组蛋白化学改性中的基因表达调控现象。

　　This modification is either the addition of methyl groups to the DNA or of acetyl groups to the histones.

　　这种改性或者是甲基增至DNA中，或者是乙酰基增加到组蛋白中。

　　Methylation switches genes⁵ off.

　　甲基化作用关闭基因，

　　Acetylation switches them on.

　　乙酰化作用启动基因。

　　Since, in a multicellular organism, different cells need different genes to be active, such regulation is vital.

　　由于在多细胞有机体中，不同的细胞需要借助不同的基因以激活自身，所以这种调控至关重要。

　　What has got a lot of people excited, though, is the idea that epigenetic switches might be transmitted down the generations.

　　但令人兴奋的是，有观点认为，表观遗传现象中的基因表达调控功能有可能世代相传。

　　Some see this as contrary to Darwinism, since it would permit characteristics acquired during an organism's lifetime to be passed on to its offspring, as suggested by a rival theory of evolution put forward by Jean-Baptiste Lamarck.

　　有些人将之视为对达尔文学说的反证，因为这将允许有机体存活期间所获得的特征遗传给后代，正如法国著名生物学家让巴蒂斯特拉马克所提出的与进化论相对的学说。

　　This is an exaggeration.

　　这种想法有些夸张了。

　　The DNA sequence itself is not being permanently⁶ altered.

　　基因序列不会一直变化，

　　Even those epigenetic changes that are inherited seem to be subsequently reversible.

　　甚至那些表观遗传学意义上的变化遗传给下一代后，似乎仍然存在可逆性。

　　But the idea that acquired characteristics can be inherited at all is still an important and novel one, and a worrying example of the phenomenon has been published this week in BioMed Central Medicine.

　　但是，因表观遗传现象所获得的特征完全可以遗传的观点仍然新颖且重要。本周，BioMed Central Medicine刊出了一项研究，可例证这一现象，其结果令人担忧。

　　The study in question, by Virender Rehan of the Los Angeles Biomedical Research Institute, and his colleagues, was of the intergenerational effects of nicotine⁷.

　　该项研究是由洛杉矶生物医学研究所的Virender Rehan和他的同事们开展的，研究的是尼古丁的代际影响。

　　It was done in rats, but a rat's physiology⁸ is sufficiently⁹ similar to a human's to suspect the same thing may be true in Homo sapiens.

　　研究人员虽然在大鼠身上进行实验，但因为大鼠的生理机能与人类十分相像，所以研究人员怀疑对于大鼠的研究结果可能同样适用于智人。

　　In a nutshell, Dr Rehan showed that if pregnant rats are exposed to nicotine, not only will their offspring develop the asthma¹⁰ induced by this drug, so will the offspring of those offspring.

　　简而言之，Rehan博士想说明的是，如果大鼠怀孕时接触尼古丁，不仅下一代会因此患上哮喘，第三代也会深受其害。

　　Dr Rehan and his team injected their rats with nicotine when they were six days pregnant.

　　Rehan博士和他的团队在大鼠怀孕的第六天为其注射尼古丁。

　　They then allowed them to give birth and raised the pups to the age of three weeks, before some were examined.

　　大鼠的后代出生后，由母鼠养育三周。

　　The rest were allowed to mature and breed, and their own offspring were similarly examined.

　　然后研究人员选取一部分后代进行检查，其余的第二代大鼠继续生长繁殖，最后研究人员对第三代大鼠进行类似的检验。

　　There was, however, no further administration of nicotine.

　　但是，第二代大鼠在妊娠期间，不再被注射尼古丁。

　　The pups of the treated mothers had asthmatic lungs.

　　检测发现，被注射尼古丁的母鼠所繁殖的第二代大鼠肺部有哮喘病变。

　　The organs' airways¹¹ were constricted¹²,

　　大鼠肺部的气道处于收缩状态。

　　and molecular¹³ analysis showed abnormally high levels of fibronectin and collagen—which would stiffen¹⁴ the lung tissue—and also high levels of receptor molecules¹⁶ for nicotine.

　　经过分子分析发现，大鼠肺部的纤维连接蛋白和胶原蛋白含量异常升高，这将导致肺组织硬化；同时尼古丁受体分子增加。

　　That was expected, since the developing embryos¹⁷ were exposed to the nicotine when their mothers were treated.

　　结果表明，母鼠被注射尼古丁后，其后代在胚胎发育时期就会受尼古丁的影响，这一结果正如预期。

　　However, when the team did similar tests on the grand-offspring of the treated mothers, they got similar results.

　　但是，当研究团队对第三代大鼠进行类似检查时，发现了同样的情况，

　　Those grand-offspring had not been exposed to nicotine.

　　即使这些第三代大鼠并没有接触尼古丁。

　　The cause of the grand-offsprings' asthma, Dr Rehan believes, is epigenetic modification.

　　Rehan博士认为，第三代大鼠的哮喘是表观遗传中的改性现象。

　　Nicotine is not only affecting lung cells, but also affecting sex cells in ways that cause the lungs which ultimately develop from those cells to express their genes in the same abnormal ways.

　　尼古丁不仅侵袭肺部细胞，还会影响生殖细胞，使得生殖细胞在发育器官时，在肺部异常表达基因，导致新发育的肺部同样受到尼古丁的不良影响。

　　Exactly what those epigenetic changes are is hard to track down.

　　表观遗传现象具体引起了哪种变化，目前难以获知。

　　The team have started looking, but could find no clear pattern except that one form of nicotine-induced acetylation, that of H3 histones, could be blocked by a molecule¹⁵ called RGZ.

　　研究团队已经开始研究这一问题，但目前只研究出一种明确的模式：尼古丁会引起H3组蛋白的乙酰化，

　　This molecule is also known to protect lungs against the asthma-causing effects of nicotine.

　　进而导致一种叫做RGZ的分子受到抑制，而目前已知RGZ分子可以保护肺脏，使其免受由尼古丁引起的哮喘。

　　That suggests it is the acetylation of H3 histones rather than the methylation of DNA itself that is creating the effect.

　　这表明由尼古丁引起的哮喘是源于H3组蛋白的乙酰化，而非DNA自身的甲基化作用。

　　Which crucial genes these histones surround remains¹⁸ obscure.

　　研究团队目前没有研究出这些受影响的组蛋白包含着哪些关键基因，

　　Nor have the team yet found out whether the epigenetic effect they have discovered reaches further than grand-offspring.

　　也没有发现表观遗传的影响是否会延续至第三代以下的后代。

　　If it does, though, it suggests that epigenetics really might act like the biblical curse:

　　然而，如果有研究表明后生效应会世代相传的话，这就表明表观遗传现象真真是有如圣经上的诅咒：

　　that the sins of the fathers will be visited on the sons, even unto the third and fourth generations.

　　父辈的罪孽，会降罪至他们的下一代身上，甚至会延续至第三代或者第四代。

　　1.refer to 涉及；指的是

　　Symbols are signs that refer to the object by a convention.

　　标志是一种人们习惯性指代某种事物的符号。

　　Slowschools and slow education can refer to different aspects of education.

　　慢速学校和慢速教育可以指教育的不同方面。

　　2.seem to 似乎

　　Financial markets seem to agree.

　　金融市场似乎也证实了这一点。

　　Investors¹⁹ seem to have noticed.

　　投资者似乎也注意到了。

　　3.similar to 相似,相同

　　You should see something similar to figure 2.

　　你应该会看到类似图2的内容。

　　Try and visualize²⁰ this energy as a bright white light similar to that of sunlight.

　　试着想象这一能源，把它当做一种明亮如阳光一样的白光。

　　4.expose to 暴露于；公开揭露

　　When expose to hydrogen sulfide in extremely high concentration, "shock-like" poisoning may appear. The sufferer may suddenly fall in seconds and stop breathing.

　　在接触极高浓度硫化氢时，可发生“电击样”中毒，接触者在数秒内突然倒下，呼吸停止。

　　To expose to danger or harm.

　　暴露于危险和伤害之下。

1 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。

2 strictly   

adv.严厉地，严格地；严密地

参考例句：

• His doctor is dieting him strictly.他的医生严格规定他的饮食。
• The guests were seated strictly in order of precedence.客人严格按照地位高低就座。

3 modification   

n.修改，改进，缓和，减轻

参考例句：

• The law,in its present form,is unjust;it needs modification.现行的法律是不公正的，它需要修改。
• The design requires considerable modification.这个设计需要作大的修改。

4 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。

5 genes   

n.基因( gene的名词复数 )

参考例句：

• You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因，所以能够活得很长。 来自《简明英汉词典》
• Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪

6 permanently   

adv.永恒地，永久地，固定不变地

参考例句：

• The accident left him permanently scarred.那次事故给他留下了永久的伤疤。
• The ship is now permanently moored on the Thames in London.该船现在永久地停泊在伦敦泰晤士河边。

7 nicotine   

n.(化)尼古丁，烟碱

参考例句：

• Many smokers who are chemically addicted to nicotine cannot cut down easily.许多有尼古丁瘾的抽烟人不容易把烟戒掉。
• Many smokers who are chemically addicted to nicotine cannot cut down easily.许多有尼古丁瘾的抽烟人不容易把烟戒掉。

8 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

9 sufficiently   

adv.足够地，充分地

参考例句：

• It turned out he had not insured the house sufficiently.原来他没有给房屋投足保险。
• The new policy was sufficiently elastic to accommodate both views.新政策充分灵活地适用两种观点。

10 asthma   

n.气喘病，哮喘病

参考例句：

• I think he's having an asthma attack.我想他现在是哮喘病发作了。
• Its presence in allergic asthma is well known.它在过敏性气喘中的存在是大家很熟悉的。

11 AIRWAYS   

航空公司

参考例句：

• The giant jets that increasingly dominate the world's airways. 越来越称雄于世界航线的巨型喷气机。
• At one point the company bought from Nippon Airways a 727 jet. 有一次公司从日本航空公司买了一架727型喷气机。

12 constricted   

adj.抑制的，约束的

参考例句：

• Her throat constricted and she swallowed hard. 她喉咙发紧，使劲地咽了一下唾沫。
• The tight collar constricted his neck. 紧领子勒着他的脖子。

13 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。

14 stiffen   

v.(使)硬，(使)变挺，(使)变僵硬

参考例句：

• The blood supply to the skin is reduced when muscles stiffen.当肌肉变得僵硬时，皮肤的供血量就减少了。
• I was breathing hard,and my legs were beginning to stiffen.这时我却气吁喘喘地开始感到脚有点僵硬。

15 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

16 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。

17 embryos   

n.晶胚；胚，胚胎( embryo的名词复数 )

参考例句：

• Somatic cells of angiosperms enter a regenerative phase and behave like embryos. 被子植物体细胞进入一个生殖阶段，而且其行为象胚。 来自辞典例句
• Evolution can explain why human embryos look like gilled fishes. 进化论能够解释为什么人类的胚胎看起来象除去了内脏的鱼一样。 来自辞典例句

18 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

19 investors   

n.投资者，出资者( investor的名词复数 )

参考例句：

• a con man who bilked investors out of millions of dollars 诈取投资者几百万元的骗子
• a cash bonanza for investors 投资者的赚钱机会

20 visualize   

vt.使看得见，使具体化，想象，设想

参考例句：

• I remember meeting the man before but I can't visualize him.我记得以前见过那个人，但他的样子我想不起来了。
• She couldn't visualize flying through space.她无法想像在太空中飞行的景象。