The Ghost In Your Genes - 4 基因外遗传现象

...lead to the end of diseases like cancer...

Alzheimer's, Parkinson's, diabetes¹.

The list is endless.

We were thinking of genes² in a very mechanical way. We were thinking of them just in terms of the sequence of the letters when we were working out how we could work out what all the letters were in the book.

Scientists estimated that the human genome, the book of life, would contain around 100,000 genes.

And then when they started sequencing they, they realized there may be 100,000 genes, and it popped down to 60, and then it popped down to 50, I mean, and slowly went down to a much smaller number. In fact we found out that the human genome is probably not as complex and doesn't have as many genes as, as plants do. So that they made us really question it all. If the genome has less genes in this species versus³ this species, and we are more complex potentially, what's going on here?

Now, scientists estimate there are probably less than 30,000 genes.

We believed, I believed naively⁴ that we would be able to find the genetic⁵ components⁶ of common diseases. That's proven to be very difficult. The idea of one-gene-one-disease does not explain it all.

30,000 genes didn't appear enough to explain human complexity⁷. There had to be something they'd missed. The first hints of what was missing lay in the curious paradox⁸ of the Prader-Willi and Angelman syndromes¹⁰, two quite different diseases caused by exactly the same genetic fault. When Pembrey looked at the inheritance pattern for their conditions he noticed something even stranger.

What really mattered was the origin of the Chromosome¹¹ 15 that had the deletion. If the deletion was on the Chromosome 15 that the child had inherited from father then you had Prader-Willi syndrome⁹. Whereas, if the, er, deletion, er, was inherited from the mother, er, you had the Angelman syndrome.

It was a complete surprise that the same missing strip of DNA¹² could cause one disease when it came from the mother and a completely different disease when it came from the father. It was as if the genes knew where they came from.

You've got a developing fetus¹³ manifesting this condition. How does the Chromosome 15 know where it came from? It, there must have been a tag or an imprint¹⁴ placed on that chromosome during either egg or sperm¹⁵ formation in the previous generation to, to say "Hi, I came from mother, I came from father" and we are functioning differently. So that's the key thing that although the DNA sequence is the same the different sets of genes were being silenced depending on whether it came from the mother or from the father.

New Words & Phrases:

Alzheimer's: Alzheimer's disease is a condition in which a person's brain gradually stops working properly. 【医】阿耳茨海默氏病,早老性痴呆病

Parkinson's: 【医】帕金森氏病
fetus : (= foetus)A fetus is an animal or human being in its later stages of development before it is born. 胎;(三个月后的)胎儿

1 diabetes   

n.糖尿病

参考例句：

• In case of diabetes, physicians advise against the use of sugar.对于糖尿病患者，医生告诫他们不要吃糖。
• Diabetes is caused by a fault in the insulin production of the body.糖尿病是由体內胰岛素分泌失调引起的。

2 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

3 versus   

prep.以…为对手，对；与…相比之下

参考例句：

• The big match tonight is England versus Spain.今晚的大赛是英格兰对西班牙。
• The most exciting game was Harvard versus Yale.最富紧张刺激的球赛是哈佛队对耶鲁队。

4 naively   

adv. 天真地

参考例句：

• They naively assume things can only get better. 他们天真地以为情况只会变好。
• In short, Knox's proposal was ill conceived and naively made. 总而言之，诺克斯的建议考虑不周，显示幼稚。

5 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。

6 components   

（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分

参考例句：

• the components of a machine 机器部件
• Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。

7 complexity   

n.复杂(性)，复杂的事物

参考例句：

• Only now did he understand the full complexity of the problem.直到现在他才明白这一问题的全部复杂性。
• The complexity of the road map puzzled me.错综复杂的公路图把我搞糊涂了。

8 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。

9 syndrome   

n.综合病症；并存特性

参考例句：

• The Institute says that an unidentified virus is to blame for the syndrome. 该研究所表示,引起这种综合症的是一种尚未确认的病毒。
• Results indicated that 11 fetuses had Down syndrome. 结果表明有11个胎儿患有唐氏综合征。

10 syndromes   

n.综合征( syndrome的名词复数 )；（某种条件下有共同特征的）一系列表现（事件、举动等）

参考例句：

• Other agents can cause similar syndromes. 其它病原也可引起相似的综合症。 来自辞典例句
• They have pointed out the similarities of the sprue syndromes in man and TGE. 他们强调了人的鹅口疮综合症和TGE的共同点。 来自辞典例句

11 chromosome   

n.染色体

参考例句：

• Chromosome material with exhibits of such behaviour is called heterochromatin.表现这种现象的染色体物质叫做异染色质。
• A segment of the chromosome may become lost,resulting in a deletion.染色体的一个片段可能会丢失，结果产生染色体的缺失。

12 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。

13 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。

14 imprint   

n.印痕，痕迹；深刻的印象；vt.压印，牢记

参考例句：

• That dictionary is published under the Longman imprint.那本词典以朗曼公司的名义出版。
• Her speech left its imprint on me.她的演讲给我留下了深刻印象。

15 sperm   

n.精子，精液

参考例句：

• Only one sperm fertilises an egg.只有一个精子使卵子受精。
• In human reproduction,one female egg is usually fertilized by one sperm.在人体生殖过程中，一个精子使一个卵子受精。