The race to sequence the human genome - Tien Nguyen

譯者: Ann Chen 審譯者: Max Chern

Packed inside every cell in your body is a set of genetic instructions,

在你身體每個細胞裡都有一組遺傳指令

3.2 billion base pairs long.

有 32 億個鹼基對的長度

Deciphering these directions would be a monumental task

要解讀這些指令將是一個工程浩大的任務

but could offer unprecedented insight about the human body.

但可提供關於人體未知的訊息

In 1990, a consortium of 20 international research centers

在 1990 年，一個由 20 個 國際研究中心組成的協會

embarked on the world's largest biological collaboration

著手於世界最大的生物合作研究

to accomplish this mission.

來完成這個任務

The Human Genome Project proposed to sequence the entire human genome

“人類基因組計劃” 打算 測序整個人類基因組

over 15 years with $3 billion of public funds.

以 30 億公共資金，在 15 年內完成

Then, seven years before its scheduled completion,

然而，在離既定計畫完成的七年前

a private company called Celera announced that they could accomplish the same goal

一個名為 “塞雷拉” 的私人公司 聲稱他們只要用三年的時間

in just three years and at a fraction of the cost.

並且只要用更少的經費 就能完成相同的目標

The two camps discussed a joint venture, but talks quickly fell apart

雙邊陣營討論合作研究， 但商談很快就破裂了

as disagreements arose over legal and ethical issues of genetic property.

因為對於基因財產權的合法性 與道德性議題意見不合

And so the race began.

所以競賽開始了

Though both teams used the same technology to sequence the entire human genome,

雖然雙方使用相同的技術 來測序整個人類基因組

it was their strategies that made all the difference.

但他們不同的策略 使得整個過程大不相同

Their paths diverged in the most critical of steps:

他們在最關鍵性的步驟有很大的差異：

the first one.

也就是第一個步驟

In the Human Genome Project's approach,

在人類基因組計劃的研究方法

the genome was first divided into smaller, more manageable chunks

基因組先被切成較小 且容易處理的片斷

about 150,000 base pairs long

約是 15 萬個鹼基對的長度

that overlapped each other a little bit on both ends.

兩邊末端稍有相互重疊

Each of these fragments of DNA

每個去氧核醣核酸 （DNA）的片斷

was inserted inside a bacterial artificial chromosome

被植入到細菌人工染色體裡

where they were cloned and fingerprinted.

在此，它們被複製並標示印記

The fingerprints showed scientists where the fragments overlapped

這些印記讓科學家在不清楚 實際基因排序的情況之下

without knowing the actual sequence.

知道這些片斷在哪裡重疊

Using the overlapping bits as a guide,

利用重疊的部分當作指引

the researchers marked each fragment's place in the genome

研究人員標記每個片斷在基因組的位置

to create a contiguous map,

藉此畫出一個連續性的圖譜

a process that took about six years.

這個過程花了大約六年的時間

The cloned fragments were sequenced in labs around the world

複製片斷在世界各地的實驗室進行測序

following one of the project's two major principles:

遵循此計劃的兩大主要原則之一：

that collaboration on our shared heritage was open to all nations.

對於我們有著共同起源的基因 之研究結果要公開給全世界

In each case, the fragments were arbitrarily broken up

每個實驗，這些片斷被任意 再切成較小重疊的片斷

into small, overlapping pieces about 1,000 base pairs long.

約是 1000 個鹼基對的長度

Then, using a technology called the Sanger method,

然後，使用一種叫做 “桑格測序法” 的技術

each piece was sequenced letter by letter.

每個片斷分別一個個字母被測序出來 （指 A、T、C、G)

This rigorous map-based approach called hierarchical shotgun sequencing

這種精密以圖譜為基礎的方式 稱為 “分級霰彈槍測序法”

minimized the risk of misassembly,

把錯誤組合的風險降到最低

a huge hazard of sequencing genomes with many repetitive portions,

這是測序有很多重複部位的基因組時 會存在的巨大風險

like the human genome.

例如：人體基因組

The consortium's "better safe than sorry" approach

協會的 “安全勝過遺憾” 的要求

contrasted starkly with Celera's strategy called whole genome shotgun sequencing.

與塞雷拉公司的策略 “全基因組霰彈槍測序法” 形成明顯的對比

It hinged on skipping the mapping phase entirely,

主要關鍵在於塞雷拉 完全跳過了畫圖譜的階段

a faster, though foolhardy, approach according to some.

依據某些人的看法，這是一種 較快但有勇無謀的方法

The entire genome was directly chopped up

整個基因組直接被切成

into a giant heap of small, overlapping bits.

許許多多小而重疊的片斷

Once these bits were sequenced via the Sanger method,

一旦這些片斷用桑格方法被測序後

Celera would take the formidable risk of reconstructing the genome

塞雷拉會採取風險很大的方式 來重組基因組

using just the overlaps.

也就是只使用重疊的部分

But perhaps their decision wasn't such a gamble

但或許他們的決定並不是那麼冒險

because guess whose freshly completed map was available online for free?

因為猜猜誰的最新完整圖譜 可以在網上免費獲得？

The Human Genome Consortium,

人類基因組計劃協會符合

in accordance with the project's second major principle

研究計畫的第二個主要原則

which held that all of the project's data

將研究中所收集到的資料

would be shared publicly within 24 hours of collection.

在 24 小時內公開分享給大眾

So in 1998, scientists around the world

所以在 1998 年， 世界各地的科學家

were furiously sequencing lines of genetic code

熱烈地使用經過證明可信的 （雖費力的）桑格測序法

using the tried and true, yet laborious, Sanger method.

來進行遺傳密碼的測序

Finally, after three exhausting years of continuous sequencing and assembling,

最後，歷經三年竭盡所能 持續地測序與組合

the verdict was in.

判決公布了

In February 2001, both groups simultaneously published

在 2001 年二月，雙方同時發表

working drafts of more than 90% of the human genome,

超過 90% 的人類基因草圖

several years ahead of the consortium's schedule.

比協會的預定進度超前了好幾年

The race ended in a tie.

競賽以平手結束

The Human Genome Project's practice of immediately sharing its data

人類基因組計劃立即分享資料的作法

was an unusual one.

是一種不尋常的方式

It is more typical for scientists to closely guard their data

通常，科學家都小心翼翼地 保護他們的資料

until they are able to analyze it and publish their conclusions.

直到能夠分析這些資料 及發表他的結論

Instead, the Human Genome Project accelerated the pace of research

相反地，人類基因組計劃 加速了研究的腳步

and created an international collaboration on an unprecedented scale.

並創造了一個空前規模的 國際性合作研究

Since then, robust investment in both the public and private sector

自此，在公共及私人領域的大力投資

has led to the identification of many disease related genes

使得很多和疾病相關的基因 被檢測出來

and remarkable advances in sequencing technology.

同時在測序的技術上 也有非凡的進步

Today, a person's genome can be sequenced in just a few days.

現在，一個人的基因組能夠 在幾天內就被測序出來

However, reading the genome is only the first step.

然而，判讀基因組只是第一步而已

We're a long way away from understanding what most of our genes do

對於了解我們基因的功用 以及如何控制基因方面

and how they are controlled.

我們仍有漫長的路要走

Those are some of the challenges

這些是給具有野心、進取心的

for the next generation of ambitious research initiatives.

下一代研究者一些挑戰