“基因完美人”離我們有多遠

“基因完美人”離我們有多遠

Crispr基因編輯技術(shù)被吹捧為一種再造人類的手段，現(xiàn)在這種技術(shù)即將從培養(yǎng)皿走向人類。

測試中可能遇到的詞匯和知識：

muscular dystrophy 肌肉萎縮癥；營養(yǎng)不良

tout 吹捧[ta?t]

reboot 重新啟動[ri?'bu?t]

tumour 瘤；腫瘤[?tu?m?r]

bloodstream 血流['bl?dstri?m]

derail 使出軌[d?'re?l]

leukaemia 白血病[lu?'ki?m??]

unintended 無意識的；非計劃中的[?n?n'tend?d]

enzyme [生化] 酶['enza?m]

amend 修改；改善，改進[?'mend]

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4分15秒 母語為英語者的朗讀速度 140

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Gene-editing: A step closer to homo perfectus（610words）

By Anjana Ahuja

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So it begins. Nobody thought it would happen this fast, and now we are preparing to take a leap into the unknown. Not Brexit but Crispr gene-editing, a DNA-changing technology that can supposedly cure mice of liver disease and muscular dystrophy, render human cells resistant to HIV and create fungus-resistant wheat.

It has also been touted as a means of remaking humanity — and now it is about to progress from Petri dishes into people. An influential advisory panel at the US National Institutes of Health has unanimously approved the first clinical trial to use Crispr genome-editing (also known as gene-editing) on humans, to reboot immune cells in cancer patients. Researchers at the University of Pennsylvania will target patients with multiple myeloma, melanoma or sarcoma. The team will remove a class of immune cells called T-cells from patients, edit the genes of those T-cells so they are better able to “l(fā)ock on” to tumour cells, and then restore the altered T-cells back into the bloodstream.

With luck, the genetic edits should boost the patient’s immune system. The study, now expected to receive the blessing of federal regulators, will be funded by a cancer institute founded by Sean Parker of Napster and Facebook fame.

The aim of this first in-human trial of Crispr is not to enhance therapeutic outcomes but to prove its safety. Other genetic technologies of great promise cast long shadows. Gene therapy, which involves inserting copies of missing or defective genes into a patient, usually using a virus as a carrier, was nearly derailed at the turn of the millennium , when a child with a severe immune disorder developed leukaemia as a direct result of the treatment.

The viruses chosen as carriers in some early trials wrought unforeseen damage. As a result the first European treatment using gene therapy, which has been around since 1990, was licensed only in 2012. With gene-editing, the unintended consequence that most terrifies genetic researchers is “off-target effects”, in which untargeted genes are inadvertently snipped, deleted or altered. The technology uses enzymes to search for particular sequences of DNA — but, just as it is possible for a search facility in word-processing software to pick out a string of letters in an unexpected place, the enzymes might similarly latch on to the wrong stretch of DNA.

The risk, at least in this trial, is minimised by the gene-editing being done outside the body, allowing researchers to check the T-cells have been appropriately amended before being put back into the patient. Still, once the cutting enzyme is unleashed, there is a possibility it could continue operating inside the body to uncertain end.

By next year we should have a hint of whether gene-editing really can fix deficient DNA in people. And that is when things get serious: why stop at correcting the human genome? Why not beautify it? That thought is preoccupying those in the field, who raised concerns at a Washington summit in December, organised by scientists from the UK, China and the US. Among those attending was Yale University’s Daniel Kevles, a historian of the eugenics movement.

The thing about Crispr genome-editing is this: it is fast, cheap and easy to do. Many countries, especially those that see themselves as future torchbearers for technology, such as China, are forging ahead; China holds the first claim to creating a (non-viable) gene-edited embryo. Regulation is patchy.

No country endorses a genome-edited human embryo being implanted and being brought to term. Even so, gene-editing technology makes the prospect of a homo perfectus just slightly more probable — and, as a species, we have yet to fully grasp the implications of this brave and perfectly edited new world.

請根據(jù)你所讀到的文章內(nèi)容，完成以下自測題目：

1. What is the ‘T-cells’ as mentioned?

A. a kind of immune cells

B. a kind of tumour cells

C. edited cells in mouse

D. a kind of infected cells

2. What is the aim of this first in-human trial of Crispr?

A. to enhance therapeutic outcomes

B. to get more donations

C. to prove its safety

D. to recruit volunteers

3. When was the gene therapy was listened in Europe?

A. 1990

B. 2000

C. 2012

D. 2016

4. Which one is not the characteristics of Crispr genome-editing?

A. fast

B. vulnerability

C. cheap

D. easy to do

[1] 答案 A. a kind of immune cells

解釋：美國將批準首項人類Crispr基因編輯試驗。該團隊將從患者體內(nèi)取出被稱為T細胞的一類免疫細胞，對這些T細胞的基因進行編輯，使它們能更好地“鎖定”癌細胞，然后將這些修改過的T細胞重新導入患者的血液循環(huán)系統(tǒng)。

[2] 答案 C. to prove its safety

解釋：這個對人體進行的第一項Crispr實驗的目的，不是為了改善治療結(jié)果，而是為了證明其安全性。

[3] 答案 C. 2012

解釋：在一些早期的試驗中，被選為載體的病毒造成了無法預見的傷害。其結(jié)果是，基因療法雖然從1990年起就存在了，但歐洲第一例使用這種療法的治療在2012年才獲得許可。

[4] 答案 B. vulnerability

解釋：Crispr基因組編輯有這樣一個特點：這種技術(shù)快速、廉價和易行。Vulnerability是致命性。