VOA标准英语2010-Songbird Genome Could Reveal Clues to Hum

New map of zebra finch¹ DNA² could provide keys to stuttering, autism and Parkinson's disease

Véronique LaCapra | St. Louis, Missouri 05 April 2010

 
Photo: L. Brian Stauffer, University of Illinois News Bureau
The zebra finch is the first songbird to have its genome sequenced.

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Article in Nature

An international team of researchers has sequenced the genome of the zebra finch. Their work reveals a lot about songbird genetics, and opens a new door to understanding the basis of human speech.

The Australian zebra finch is named for the black and white stripes on the male's throat — he's the one who does all the singing. The zebra finch survives well in captivity⁴. That makes it both a popular pet and a favorite subject for researchers.

Model of Understanding

University of California-San Francisco psychiatrist⁵ and neuroscientist Allison Doupe got interested in finches because they provide a model for understanding how people learn to speak.

Doupe says that like human infants, songbirds have to hear adults during a critical period early in life. "Then they have to practice — their first vocalizations are like babbling⁷ in babies, and they have to hear themselves while they practice." Their songs gradually get better and better, like children learning to speak. "So it turns out that lots of the behavior is fairly similar between speech learning and songbird learning."

Songbirds are one of the few groups of animals that — like humans — are capable of vocal⁶ learning. Others include whales, elephants, and bats. Researchers have been studying the zebra finch to try to identify the genes⁸ that make this vocal learning possible.

Turning on genes

Neurobiologist David Clayton from the University of Illinois at Urbana-Champaign is one of the lead researchers in an international team that has sequenced and analyzed⁹ the genome of the zebra finch. "When a bird hears another bird singing or sings himself, this seems to engage a very large number of genes in the brain. Genes are being turned off, genes are being turned on."

A previous study by Clayton's lab had shown that, as a young finch first learns how to sing, hundreds of genes in its brain quickly respond, producing more or less protein.

Now, with a map of the whole genome in hand, the researchers looked at how individual genes in the adult finch brain respond to singing.

"We found a surprisingly large number of genes are being regulated," says Clayton.

In fact, they found that at least 800 genes spring into action in a finch's brain whenever it sings.

Not only that, but most of those genes are of a kind that scientists used to think of as molecular¹⁰ junk. Instead of producing proteins, the genes produce something called non-coding RNA.

"That non-coding RNA, well, what does it do? Well, it's not that it's going to make a protein," explains Clayton. "It's going to turn around and bind¹¹ to other RNAs, physically¹² bind to them, in a way that will then determine whether those other RNAs get made into protein or not."

Similar to humans

Wes Warren is the assistant director of the Genome Center at Washington University in St. Louis, and a leader of the finch genome sequencing project. He says that the same kinds of complex genetic³ interactions that are happening in the songbird brain are probably happening in ours.

"As you're hearing my words as I'm speaking, your brain is processing those words, and we think analogous¹³ to what's going on in the bird, there's genes in particular areas of your brain, that are being expressed very rapidly or decreased very rapidly to allow you to process that information."

Since we've heard those words before, Warren says our brain has formed a kind of "molecular memory" of them. "And your ability to decipher them and understand them and reproduce them is a response to all these genes that are being regulated in your brain."

Clues to human speech disorders¹⁴

Warren says now that researchers have a map of the zebra finch genome, they can carry out experiments to identify which genes in the finch's brain are most critical to hearing and producing song — and by extension, which genes may play a role in human speech disorders, like those related to stuttering, autism, and Parkinson's disease.

Researchers will also be able to learn more about songbird evolution.

"The songbird community as a whole I think is very excited about this," says Allison Doupe. She wasn't involved in the finch genome research but she's been looking forward to its completion. "It's really the beginning of the next age of studies of songbirds, where we're going to have lots of additional tools."

The zebra finch genome analysis is published in the latest issue of the journal Nature.

 

1 finch   

n.雀科鸣禽(如燕雀，金丝雀等)

参考例句：

• This behaviour is commonly observed among several species of finch.这种行为常常可以在几种雀科鸣禽中看到。
• In Australia,it is predominantly called the Gouldian Finch.在澳大利亚，它主要还是被称之为胡锦雀。

2 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。

3 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。

4 captivity   

n.囚禁；被俘；束缚

参考例句：

• A zoo is a place where live animals are kept in captivity for the public to see.动物园是圈养动物以供公众观看的场所。
• He was held in captivity for three years.他被囚禁叁年。

5 psychiatrist   

n.精神病专家；精神病医师

参考例句：

• He went to a psychiatrist about his compulsive gambling.他去看精神科医生治疗不能自拔的赌瘾。
• The psychiatrist corrected him gently.精神病医师彬彬有礼地纠正他。

6 vocal   

adj.直言不讳的；嗓音的；n.[pl.]声乐节目

参考例句：

• The tongue is a vocal organ.舌头是一个发音器官。
• Public opinion at last became vocal.终于舆论哗然。

7 babbling   

n.胡说，婴儿发出的咿哑声adj.胡说的v.喋喋不休( babble的现在分词 )；作潺潺声（如流水）；含糊不清地说话；泄漏秘密

参考例句：

• I could hear the sound of a babbling brook. 我听得见小溪潺潺的流水声。 来自《简明英汉词典》
• Infamy was babbling around her in the public market-place. 在公共市场上，她周围泛滥着对她丑行的种种议论。 来自英汉文学 - 红字

8 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

9 analyzed   

v.分析( analyze的过去式和过去分词 )；分解；解释；对…进行心理分析

参考例句：

• The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
• The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程，因为对他来说，爱是个不可分析的迷。 来自《简明英汉词典》

10 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。

11 bind   

vt.捆，包扎；装订；约束；使凝固；vi.变硬

参考例句：

• I will let the waiter bind up the parcel for you.我让服务生帮你把包裹包起来。
• He wants a shirt that does not bind him.他要一件不使他觉得过紧的衬衫。

12 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。

13 analogous   

adj.相似的；类似的

参考例句：

• The two situations are roughly analogous.两种情況大致相似。
• The company is in a position closely analogous to that of its main rival.该公司与主要竞争对手的处境极为相似。

14 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》