美国国家公共电台 NPR Moshe Szyf: How Do Our Experiences Rewire Our Brains And Bodies?

 

GUY RAZ, HOST:

It's the TED¹ Radio Hour from NPR. I'm Guy Raz. And on the show today, hardwired - ideas about what determines our personalities², our traits, our behaviors and even the choices we make. And usually when we talk about the way humans are wired, we're talking about our genetics, our DNA⁵.

MOSHE SZYF: Everything we do is so-called encoded in our DNA. And it comes after millions and millions of years of evolution. And that defines, essentially⁶, a lot of our lives, our future lives.

RAZ: This is Moshe Szyf. He's a professor at McGill University. And you're an epigeneticist, right?

SZYF: Yes.

RAZ: What is it, by the way?

SZYF: The field of epigenetics is interested in how genes⁷ are programmed. So if you think about our genes as some sort of a hardware of a computer, epigenetics is the software. It makes it work, right? If you buy a computer that has only hardware without software, it's useless.

RAZ: Basically Moshe tries to understand whether the DNA we inherit is fixed⁸ or whether it can change.

SZYF: Right. So this is the big, big discussion of our century. And the idea was very dominant⁹ that most of who we are is defined by the kind of genes we inherited from our ancestors. You can look at it as it gives you freedom because it makes no difference what you'll do. If you have a gene³ that you're going to be smart, you will be smart. And if you're not, don't waste your time studying. And some people believe that there are genes that make us rich, make us anxious or not anxious. So that was the general idea. But as genetic⁴ research advanced, there was a good conviction among some people that there must be something else going on in DNA, that DNA by itself is not sufficient to explain behavior.

RAZ: And Moshe has been studying this idea for decades, starting with some groundbreaking experiments with rats. Moshe Szyf tells the story from the TED stage.

(SOUNDBITE OF TED TALK)

SZYF: So it all came to life in a dark bar in Madrid. I encountered my colleague from McGill, Michael Meaney. And we were drinking a few beers. And like scientists do, he told me about his work. And he told me that he is interested in how mother rats lick their pups after they were born. And I was sitting there and saying, this is where my tax dollars are wasted...

(LAUGHTER)

SZYF: ...On this kind of soft science. And he started telling me that when the rats, like humans, lick their pups in very different ways. Some mothers do a lot of that. Some mothers do very little. And most are in between. But what's interesting about it is that when he follows these pups when they become adults - like years in human life - long after their mother died, they are completely different animals. The animals that were licked and groomed¹¹ heavily are not stressed. They have different sexual behavior. They have a different way of living than those that were not treated as intensively by her mother.

So then I was thinking to myself, is this magic? How does this work? As geneticists would like you to think, perhaps, the mother had the bad mother gene that caused her pups to be stressful. And then it was passed from generation to generation. It's all determined¹² by genetics. Or is it possible that something else is going on here? So in rats, we can ask this question and answer it. So what we did as a cross-fostering expert, you essentially separate the litter, the babies of this rat at birth to two kinds of fostering mothers, not the real mothers, but mothers that will take care of them - high-licking mothers and low-licking mothers. And the remarkable¹³ answer was it wasn't important what that gene you got from your mother. It was not the biological mother that defined this property of these rats. It is the mother that took care of the pups.

So how can this work? Is it possible that the mother is somehow reprogramming the gene of her offspring through her behavior? And we spent 10 years, and we found that there is a cascade¹⁴ of biochemical events by which the licking and grooming¹⁵ of the mother - the care of the mother - is translated to biochemical signals that go into the nucleus¹⁶ and into the DNA and program it differently. So now the animal can prepare itself for life.

RAZ: First of all, we don't think of rats being particularly maternal¹⁷. But I guess they are. I guess they can be.

SZYF: They are. And if you watch rats...

RAZ: No, thank you.

SZYF: (Laughter) You can see that they lick. They groom¹⁰. And the results are very clear that it's not the biological mother that is important in this case. It is the fostering mother.

RAZ: It's the experience.

SZYF: Yes. So it was very clear around 20 years ago that DNA has two identities - an inherited identity and another identity that is formed during embryogenesis or during the time the fetus¹⁸ develops in the womb of the mother. Of course, the next question was, does it end there? And that is, does DNA have a third identity? Which, I call it experiential identity - the identity of past experiences that somehow also use the same kind of biochemical concepts to give DNA different identities. But then this time, this will be an identity of an experience.

(SOUNDBITE OF TED TALK)

SZYF: But is it true only for rats? The problem is we cannot test this in humans because, ethically¹⁹, we cannot administer child adversity in a random²⁰ way. So if a poor child develop a certain property, we don't know whether this is caused by poverty or whether poor people have bad genes. So geneticists will try to tell you that poor people are poor because their genes make them poor. Epigeneticists will tell you poor people are in a bad environment or an impoverished²¹ environment that creates that phenotype, that property.

So we can't do experiments. We can administer adversity to humans. But God does experiments with humans. And it's called natural disasters. So one of the natural disasters - the hardest natural disaster in Canadian history happened in my province of Quebec. It's the ice storm of 1998. We lost our entire electrical grid²² because of an ice storm when the temperatures were in the dead of winter of Quebec - minus 20 to minus 30 - and there were pregnant mothers during that time.

And my colleague, Suzanne King, followed the children of these mothers for 15 years. And what happened was that as the stress increased - and here we had objective measures of stress. How long you were without power? Where did you spend your time? Was it in your mother-in-law's apartment or in some posh country home? So all these added up to a social stress scale. And you can ask the question, how did the children look like? And it appears that as stress increases, the children develop more autism. They develop more metabolic²³ diseases. And they develop more autoimmune diseases.

RAZ: So the mothers passed on the stress factor to the babies?

SZYF: Yes so we looked at their DNA, you know, when the kids were 15 years old - DNA in the blood and immune system. And we saw many, many differences in the way the epigenetics was programmed. So this, in my opinion, was, you know, one of the first evidence that in humans, too, an experience can result in long-term changes to the way genes are programmed.

RAZ: So this would suggest that we are prone²⁴ to constant change based on our environment. Or am I wrong?

SZYF: No, no, you're absolutely right. So on one hand, we have an old genome - right? - that's millions of years old that's fixed. On the other hand, we have a changing world that is talking to our DNA. And this balance, probably, was selected by many, many millions of years of evolution to provide with us with this amazing, what we call, plasticity on one hand and fixed characters on the other hand, right? So we need both. We need the immutable²⁵ and mutable operating together. And that's the amazing paradox²⁶ and challenge of life.

(SOUNDBITE OF TED TALK)

SZYF: DNA is not just a sequence of letters. It's not just a script. DNA is a dynamic movie. Our experiences are being written into that movie, which is interactive²⁷. You're like watching a movie of your life with the DNA with your remote control. You can remove an actor and add an actor. And this has a tremendous optimistic message for ability to now encounter some of the deadly diseases like cancer, mental health, with a new approach. We can epigenetically intervene, reverse the movie by removing an actor and setting up a new narrative²⁸.

RAZ: You know, Moshe, we were talking with Robert Sapolsky earlier. And he kind of questions how much free will we actually have. But - I mean, but if you say DNA is like a dynamic movie, I mean, it seems like you could also make the argument that we actually do have some agency over who we are.

SZYF: Absolutely. And I think the word agency is extremely important. And the question is, who has agency, right? Is it you as an individual? Is it you as a family? Is it you as a community? Is it you as a country? Is it you as a world? And I think all of the above. So agency is now split. It's not just you. The agency is the interactions between all these elements. If this is true, and I believe it is, there is a lot of hope. If you look at it - look at humans, what they have done in the last hundred years, we've doubled lifespan, right?

RAZ: Yeah.

SZYF: I think it's the wellbeing. I think it has to do with much lower levels of adversity in at least in some parts of the world that humans were used to for thousands of years, right? We know our next meal is there. And that knowledge, you know, removes a tremendous amount of stress from our lives. Of course, you can always argue that all of this was pre-wired. Like, the script was pre-written, including those changes. But I think that there is - between the hardwiring and the ultimate result, there is a space where freedom of will is operating. And it's operating on those epigenetic processes. If we understand these processes, tap into these processes, we can be ruler over our genes by providing the right environments. And that's where we as societies have a responsibility.

RAZ: Moshe Szyf is an epigeneticist at McGill University. You can find his full talk at ted.com.

1 ted   

vt.翻晒，撒，撒开

参考例句：

• The invaders gut ted the village.侵略者把村中财物洗劫一空。
• She often teds the corn when it's sunny.天好的时候她就翻晒玉米。

2 personalities   

n. 诽谤，（对某人容貌、性格等所进行的）人身攻击； 人身攻击；人格, 个性, 名人( personality的名词复数 )

参考例句：

• There seemed to be a degree of personalities in her remarks.她话里有些人身攻击的成分。
• Personalities are not in good taste in general conversation.在一般的谈话中诽谤他人是不高尚的。

3 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。

4 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

5 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。

6 essentially   

adv.本质上，实质上，基本上

参考例句：

• Really great men are essentially modest.真正的伟人大都很谦虚。
• She is an essentially selfish person.她本质上是个自私自利的人。

7 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

8 fixed   

adj.固定的，不变的，准备好的；(计算机)固定的

参考例句：

• Have you two fixed on a date for the wedding yet?你们俩选定婚期了吗？
• Once the aim is fixed,we should not change it arbitrarily.目标一旦确定，我们就不应该随意改变。

9 dominant   

adj.支配的，统治的；占优势的；显性的；n.主因，要素，主要的人(或物)；显性基因

参考例句：

• The British were formerly dominant in India.英国人从前统治印度。
• She was a dominant figure in the French film industry.她在法国电影界是个举足轻重的人物。

10 groom   

vt.给（马、狗等）梳毛，照料，使...整洁

参考例句：

• His father was a groom.他父亲曾是个马夫。
• George was already being groomed for the top job.为承担这份高级工作，乔治已在接受专门的培训。

11 groomed   

v.照料或梳洗（马等）( groom的过去式和过去分词 )；使做好准备；训练；（给动物）擦洗

参考例句：

• She is always perfectly groomed. 她总是打扮得干净利落。
• Duff is being groomed for the job of manager. 达夫正接受训练，准备当经理。 来自《简明英汉词典》

12 determined   

adj.坚定的；有决心的

参考例句：

• I have determined on going to Tibet after graduation.我已决定毕业后去西藏。
• He determined to view the rooms behind the office.他决定查看一下办公室后面的房间。

13 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。

14 cascade   

n.小瀑布，喷流；层叠；vi.成瀑布落下

参考例句：

• She watched the magnificent waterfall cascade down the mountainside.她看着壮观的瀑布从山坡上倾泻而下。
• Her hair fell over her shoulders in a cascade of curls.她的卷发像瀑布一样垂在肩上。

15 grooming   

n. 修饰, 美容，（动物）梳理毛发

参考例句：

• You should always pay attention to personal grooming. 你应随时注意个人仪容。
• We watched two apes grooming each other. 我们看两只猩猩在互相理毛。

16 nucleus   

n.核，核心，原子核

参考例句：

• These young people formed the nucleus of the club.这些年轻人成了俱乐部的核心。
• These councils would form the nucleus of a future regime.这些委员会将成为一个未来政权的核心。

17 maternal   

adj.母亲的，母亲般的，母系的，母方的

参考例句：

• He is my maternal uncle.他是我舅舅。
• The sight of the hopeless little boy aroused her maternal instincts.那个绝望的小男孩的模样唤起了她的母性。

18 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。

19 ethically   

adv.在伦理上，道德上

参考例句：

• Ethically , we have nothing to be ashamed about . 从伦理上说，我们没有什么好羞愧的。
• Describe the appropriate action to take in an ethically ambiguous situation. 描述适当行为采取在一个道德地模棱两可的情况。

20 random   

adj.随机的；任意的；n.偶然的(或随便的)行动

参考例句：

• The list is arranged in a random order.名单排列不分先后。
• On random inspection the meat was found to be bad.经抽查，发现肉变质了。

21 impoverished   

adj.穷困的，无力的，用尽了的v.使（某人）贫穷( impoverish的过去式和过去分词 )；使（某物）贫瘠或恶化

参考例句：

• the impoverished areas of the city 这个城市的贫民区
• They were impoverished by a prolonged spell of unemployment. 他们因长期失业而一贫如洗。 来自《简明英汉词典》

22 grid   

n.高压输电线路网；地图坐标方格；格栅

参考例句：

• In this application,the carrier is used to encapsulate the grid.在这种情况下，要用载体把格栅密封起来。
• Modern gauges consist of metal foil in the form of a grid.现代应变仪则由网格形式的金属片组成。

23 metabolic   

adj.新陈代谢的

参考例句：

• Impressive metabolic alternations have been undergone during embryogenesis.在胚胎发生期间经历了深刻的代谢变化。
• A number of intoxicants are associated with metabolic acidosis.许多毒性物质可引起代谢性酸中毒。

24 prone   

adj.(to)易于…的，很可能…的；俯卧的

参考例句：

• Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
• He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。

25 immutable   

adj.不可改变的，永恒的

参考例句：

• Nothing in the world is immutable.世界没有一成不变的东西。
• They free our minds from considering our world as fixed and immutable.它们改变着人们将世界看作是永恒不变的观点。

26 paradox   

n.似乎矛盾却正确的说法；自相矛盾的人(物)

参考例句：

• The story contains many levels of paradox.这个故事存在多重悖论。
• The paradox is that Japan does need serious education reform.矛盾的地方是日本确实需要教育改革。

27 interactive   

adj.相互作用的，互相影响的，（电脑）交互的

参考例句：

• The psychotherapy is carried out in small interactive groups.这种心理治疗是在互动的小组之间进行的。
• This will make videogames more interactive than ever.这将使电子游戏的互动性更胜以往。

28 narrative   

n.叙述，故事；adj.叙事的，故事体的

参考例句：

• He was a writer of great narrative power.他是一位颇有记述能力的作家。
• Neither author was very strong on narrative.两个作者都不是很善于讲故事。