经济学人69:外因遗传与压力 新生儿蓝调曲

 　　Science and Technology Epigenetics and stress Baby blues²

　　科技 外因遗传与压力 新生儿蓝调曲

　　A mother's stress while she is pregnant can have a long-lasting effect on her children's genes³

　　母亲孕期压力过大会对孩子的基因造成长期影响

　　RESEARCHERS have known for years that children whose mothers were chronically⁴ stressed during pregnancy⁵—by famine, anxiety, the death of a relative or marital⁶ discord⁷, for instance—show higher-than-normal rates of various psychological and behavioural disorders⁸ when they are adults.

　　研究人员多年前就发现，如果母亲在怀孕期间长期遭受因饥饿，焦虑，亲友死亡或婚姻不幸等引起的过大压力，她们的孩子成年后出现各种心理疾病和行为问题的几率会高于平均几率。

　　They have also known for a long time that those brought up in abusive environments often turn out to be abusive themselves.

　　研究人员也早知道，在受虐环境下成长起来的孩子长大后往往本身也有施虐倾向。

　　The second of these observations is usually put down to learning.The reason for the first has remained unclear.

　　人们通常把后面的这个发现归咎于盲目效仿，而头一个发现的原因却仍旧模糊不清。

　　A study just published by Axel Meyer, Thomas Elbert and their colleagues at the University of Konstanz in Germany, however, points to a phenomenon called epigenetics as the likely answer.

　　然而，德国康士坦茨大学的Axel Meyer, Thomas Elbert以及他们的同侪们最近发表的研究报告指出，一种被称为"外因遗传"的现象很有可能就是这个问题的答案。

　　And if Drs Meyer and Elbert are right, it also suggests an alternative explanation for the inheritance of abusiveness.

　　如果Meyer和Elbert博士的结论是正确的，那它也为施虐遗传现象做出了另一个解释。

　　Epigenetics is a type of gene¹ regulation that can be passed from a cell to its daughters. The most common mechanism⁹ is methylation.

　　外因遗传是一种可以传给下一代细胞的基因调控过程，

　　This attaches methyl groups (a carbon atom and three hydrogens) to either adenine or cytosine,

　　最常见的方式是通过甲基化作用来完成，该作用可以让甲基（由一个碳原子和三个氢原子组成）附着于腺嘌呤或胞嘧啶上。

　　two of the four chemical bases that form the alphabet of DNA¹⁰, depending on the gene involved.

　　腺嘌呤和胞嘧啶是DNA四大成分其中之二，而到底附着于哪一个则取决于具体的基因。

　　The consequence is to inactivate¹¹ the gene being methylated.

　　甲基化作用将使甲基化的基因失去活性。

　　In the case of stress, previous studies have suggested that methylation of the gene which encodes glucocorticoid receptors is important.

　　以往的研究表明，当母亲压力过大时，负责为糖皮质激素受体编码的基因的甲基化具有重要意义。

　　Glucocorticoid receptors relay signals from stress hormones¹² in the blood into cells.

　　糖皮质激素受体依靠血液中的压力激素发出信号而进入细胞。

　　In particular, they do so in those regions of the brain that control behaviour.

　　尤其值得注意的是，这个过程在大脑中控制人体行为的区域进行。

　　Newborns whose mothers suffered from depression while they were pregnant are known to have more highly methylated glucocorticoid-receptor genes than others.

　　新生儿的母亲若是在怀孕期间出现抑郁症状，他们糖皮质激素受体基因的甲基化程度就会比其他新生儿更高。

　　The same is true of children who were abused when young.

　　幼时受虐的孩子在这一点上也有相同表现。

　　In infants, the level of glucocorticoid-receptor methylation is correlated with the release, in response to stress, of higher-than-normal amounts of stress hormones.

　　胎儿糖皮质激素的甲基化程度与人体抑郁时分泌过多的压力激素有关。

　　And in rats, such methylation makes young animals especially sensitive to stress, and also fearful of novelty.

　　而老鼠试验表明，这样的甲基化过程让幼小动物对压力尤其敏感，对新鲜事物也感到恐惧。

　　What has been unclear until now, however, is how long such effects persist.

　　然而，现在还没弄清楚的是，这样的效应会持续多久。

　　Dr Meyer's and Dr Elbert's study, published in Translational Psychiatry¹³, offers a clue.

　　Meyer博士和Elbert博士在《转化精神病学》杂志中发表的研究报告给出了答案。

　　Troubled teens

　　问题青少年

　　Their team examined the methylation of the glucocorticoid-receptor gene in a group of children ranging in age from ten to 19 years, and in those children's mothers. The researchers also used a psychological survey to try to determine which of the mothers had been physically¹⁴ or psychologically abused before, during or after pregnancy.

　　他们的研究小组对一组年龄从10岁到19岁不等的青少年以及他们母亲体内糖皮质激素受体基因的甲基化程度进行了测量，还通过心理测试试着找出哪些母亲在孕期中或者生产后曾遭到身体或者心理上的虐待。

　　They found that women abused during pregnancy were significantly more likely than others to have a child with methylated glucocorticoid-receptor genes.

　　研究发现，孕期中遭到虐待的母亲生下糖皮质激素受体基因被甲基化的幼儿的可能性要比其他母亲高出得多。

　　By contrast, abuse before or after pregnancy resulted in no such correlation¹⁵. Nor was the mother's own methylation affected¹⁶ by violence towards her.

　　相反，在孕前或是生产后遭到虐待的母亲则不会生下这样的幼儿，而且她们本身基因的甲基化与否也跟是否遭到家庭暴力无关。

　　Taken together, these results suggest that glucocorticoid-receptor-gene methylation happens in the fetus¹⁷ in response to a mother's stress, and persists into adolescence¹⁸.

　　总体看来，这些结论表明胎儿糖皮质激素受体基因的甲基化是由于母亲压力过大引起的，并且其影响将会持续到青春期。

　　This has implications for those adolescents' long-term health.

　　这会影响青春期孩子的长期健康。

　　Dampened glucocorticoid-receptor-gene activity has been shown to increase the risk of obesity¹⁹, of depression and of some autoimmune diseases. It also makes people more impulsive²⁰ and aggressive—and therefore,

　　事实证明，糖皮质激素受体基因不够活跃会增加孩子患肥胖症，抑郁症以及某些免疫系统疾病的风险，也会让他们成年后个性更加冲动，更加富有侵略性。

　　if male, more likely to abuse the pregnant mothers of their children, thus perpetuating²¹ the whole sorry cycle.

　　因此，如果孩子是男性，他们更有可能施虐于怀着自己孩子的待产妇女，从而造成持续的恶性循环。

　　Why, in light of such negative effects, have humans evolved to be programmed this way while still in the womb?

　　发现了这种消极效应后，科学家们不禁问道，为何人类还在子宫内的时候就被设立了这样的一个进化程序呢？

　　Part of the answer is probably that not all the negative consequences would have shown up at the time the mechanism was evolving.

　　也许部分原因是，当甲基化作用还在进化的时候所有的消极影响不会当即全部表现出来。

　　Obesity, for example, is rare in a state of nature.

　　例如肥胖症在极少数情况下是天生的。

　　The other part is that some of the consequences probably have a positive effect.

　　还有一个原因是，部分消极影响也许会带来积极效应。

　　If a mother lives in an environment where fear-inducing experiences are common, say, giving her offspring a sensitivity to fear may be no bad thing.

　　如果母亲生活在一个很容易产生害怕心理的环境里，那么让她的后代对害怕情绪敏感也许并不是坏事。

　　What can be done with such knowledge is unclear.

　　知道了这些真相对人们有什么意义尚不明确。

　　Drugs that demethylate DNA are under development, but are still some way from approval—and, in any case, interfering²² with epigenetics, which is a widespread mechanism of gene regulation, is a drastic approach.

　　让DNA反甲基化的药物还在研发中，并且还未通过临床证明。另外，外因遗传是基因调控的常见手段。从任何角度来说，干预外因遗传都是一种极端激进的做法。

　　The research might, though, point to the period when intervening to stop abuse will have the greatest effect.

　　但这项研究也许会把科学家们引向另一个方向，那就是找出对基因调控进行干涉从而阻止家庭暴力的最有效时期。

　　Then again, such intervention²³ is always desirable, for the sake of both mother and child.

　　为了让母亲和孩子们都幸福，这样的干涉乃众望所归。

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 blues   

n.抑郁，沮丧；布鲁斯音乐

参考例句：

• She was in the back of a smoky bar singing the blues.她在烟雾弥漫的酒吧深处唱着布鲁斯歌曲。
• He was in the blues on account of his failure in business.他因事业失败而意志消沉。

3 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

4 chronically   

ad.长期地

参考例句：

• Similarly, any pigment nevus that is chronically irritated should be excised. 同样，凡是经常受慢性刺激的各种色素痣切勿予以切除。
• People chronically exposed to chlorine develop some degree of tolerance. 人长期接触氯气可以产生某种程度的耐受性。

5 pregnancy   

n.怀孕，怀孕期

参考例句：

• Early pregnancy is often accompanied by nausea.怀孕早期常有恶心的现象。
• Smoking during pregnancy increases the risk of miscarriage.怀孕期吸烟会增加流产的危险。

6 marital   

adj.婚姻的，夫妻的

参考例句：

• Her son had no marital problems.她的儿子没有婚姻问题。
• I regret getting involved with my daughter's marital problems;all its done is to bring trouble about my ears.我后悔干涉我女儿的婚姻问题, 现在我所做的一切将给我带来无穷的烦恼。

7 discord   

n.不和，意见不合，争论，（音乐）不和谐

参考例句：

• These two answers are in discord.这两个答案不一样。
• The discord of his music was hard on the ear.他演奏的不和谐音很刺耳。

8 disorders   

n.混乱( disorder的名词复数 )；凌乱；骚乱；（身心、机能）失调

参考例句：

• Reports of anorexia and other eating disorders are on the increase. 据报告，厌食症和其他饮食方面的功能紊乱发生率正在不断增长。 来自《简明英汉词典》
• The announcement led to violent civil disorders. 这项宣布引起剧烈的骚乱。 来自《简明英汉词典》

9 mechanism   

n.机械装置；机构，结构

参考例句：

• The bones and muscles are parts of the mechanism of the body.骨骼和肌肉是人体的组成部件。
• The mechanism of the machine is very complicated.这台机器的结构是非常复杂的。

10 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。

11 inactivate   

v.使…不活跃

参考例句：

• We put bacteria in an environment at low temperature to inactivate them.我们将细菌置於低温的环境中使之失去活性。
• Food processing destroys some nutrients,but can also inactivate toxins and increase the availability of other nutrients.食物加工破坏一些营养物质，但也可以灭活毒素，并增加其他营养物质的可用性。

12 hormones   

n. 荷尔蒙，激素 名词hormone的复数形式

参考例句：

• This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
• The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。

13 psychiatry   

n.精神病学，精神病疗法

参考例句：

• The study appeared in the Amercian science Journal of Psychiatry.这个研究发表在美国精神病学的杂志上。
• A physician is someone who specializes in psychiatry.精神病专家是专门从事精神病治疗的人。

14 physically   

adj.物质上，体格上，身体上，按自然规律

参考例句：

• He was out of sorts physically,as well as disordered mentally.他浑身不舒服，心绪也很乱。
• Every time I think about it I feel physically sick.一想起那件事我就感到极恶心。

15 correlation   

n.相互关系，相关，关连

参考例句：

• The second group of measurements had a high correlation with the first.第二组测量数据与第一组高度相关。
• A high correlation exists in America between education and economic position.教育和经济地位在美国有极密切的关系。

16 affected   

adj.不自然的，假装的

参考例句：

• She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
• His manners are affected.他的态度不自然。

17 fetus   

n.胎，胎儿

参考例句：

• In the fetus,blood cells are formed in different sites at different ages.胎儿的血细胞在不同时期生成在不同的部位。
• No one knows why a fetus is not automatically rejected by the mother's immune system. 没有人知道为什么母亲的免疫系统不会自动排斥胎儿。

18 adolescence   

n.青春期，青少年

参考例句：

• Adolescence is the process of going from childhood to maturity.青春期是从少年到成年的过渡期。
• The film is about the trials and tribulations of adolescence.这部电影讲述了青春期的麻烦和苦恼。

19 obesity   

n.肥胖，肥大

参考例句：

• One effect of overeating may be obesity.吃得过多能导致肥胖。
• Sugar and fat can more easily lead to obesity than some other foods.糖和脂肪比其他食物更容易导致肥胖。

20 impulsive   

adj.冲动的，刺激的；有推动力的

参考例句：

• She is impulsive in her actions.她的行为常出于冲动。
• He was neither an impulsive nor an emotional man,but a very honest and sincere one.他不是个一冲动就鲁莽行事的人，也不多愁善感.他为人十分正直、诚恳。

21 perpetuating   

perpetuate的现在进行式

参考例句：

• Revenge leads to a self-perpetuating cycle of violence. 怨怨相报会导致永不休止的暴力。
• It'set out to eradicate heresy, and ended by perpetuating it. 它的目的只是要根除异端邪说，结果却巩固了异端邪说。 来自英汉文学

22 interfering   

adj. 妨碍的 动词interfere的现在分词

参考例句：

• He's an interfering old busybody! 他老爱管闲事！
• I wish my mother would stop interfering and let me make my own decisions. 我希望我母亲不再干预，让我自己拿主意。

23 intervention   

n.介入，干涉，干预

参考例句：

• The government's intervention in this dispute will not help.政府对这场争论的干预不会起作用。
• Many people felt he would be hostile to the idea of foreign intervention.许多人觉得他会反对外来干预。