从最古老DNA中瞥见郁郁葱葱的北极(上)

在格陵兰岛北部边缘的永久冻土中，科学家们发现了已知最古老的DNA片段，让人们难得看到了一个不同寻常的古代生态系统。

双语精读

Oldest Known DNA Offers Glimpse of a Once-Lush Arctic

从已知最古老的DNA中窥见曾经郁郁葱葱的北极

In the permafrost at the northern edge of Greenland, scientists have discovered the oldest known fragments of DNA, offering an extraordinary look at an extraordinary ancient ecosystem.

在格陵兰岛北部边缘的永久冻土中，科学家们发现了已知最古老的DNA片段，让人们难得看到了一个不同寻常的古代生态系统。

The genetic material dates back at least two million years -- that's nearly twice as old as the mammoth DNA in Siberia that held the previous record.

这种遗传物质至少可以追溯到200万年前----比此前纪录保持者西伯利亚猛犸象的DNA要古老一倍。

And the samples, described on Wednesday in the journal Nature, came from more than 135 different species. Together, they show that a region just 600 miles from the North Pole was once covered by a forest of poplar and birch trees inhabited by mastodons.

这些样本来自超过135个不同的物种，在周三的《自然》期刊上进行了描述。它们共同表明，距离北极仅600英里的一个地区曾经被白杨树和桦树森林所覆盖，这里也曾是乳齿象的栖息地。

The forests were also home to caribou and Arctic hares. And the warm coastal waters were filled with horseshoe crabs, a species that today cannot be found any farther north of Maine. Independent experts hailed the study as a major advance.

这些森林也是驯鹿和北极野兔的家园。温暖的沿海水域充满了马蹄蟹，这一物种如今在缅因州以北的地方已难寻踪迹。独立专家称赞这项研究是一项重大进步。

"It feels almost magical to be able to infer such a complete picture of an ancient ecosystem from tiny fragments of preserved DNA," said Beth Shapiro, a paleogeneticist at the University of California, Santa Cruz.

"从保存下来的DNA微小片段中推断出一个古老生态系统的完整图景，这让人感觉很神奇。"加州大学圣克鲁斯分校的古遗传学家贝丝·夏皮罗说。

"I think it's going to blow people's minds," said Andrew Christ, a geoscientist at the University of Vermont who studies the ancient Arctic. "It certainly did so for me."

"我认为这会让人们大为震惊。"佛蒙特大学研究古代北极的地球科学家安德鲁·克罗斯说，"反正已经让我感到吃惊了。"

The discovery came after two decades of scientific gambles and frustrating setbacks.

这一发现是历经了二十年的科学赌博和令人沮丧的挫折之后取得的。

One of the leaders of the project, Eske Willerslev, pioneered methods for pulling DNA out of sediment while he was a graduate student at the University of Copenhagen.

该项目的领导者之一埃斯克·威勒斯列夫在哥本哈根大学读研究生时，就开创了从沉积物中提取DNA的方法。

In 2003, studying a chunk of Siberian permafrost, he and his colleagues found DNA from plants such as willow and daisies dating 400,000 years ago. That discovery set a record for the oldest DNA, and many scientists doubted it would be possible to find anything much older.

2003年，在研究西伯利亚的一大块永久冻土时，他和同事们发现了40万年前柳树和雏菊等植物的DNA。这一发现创造了最古老的DNA纪录，许多科学家怀疑是否有可能发现更古老的东西。

But in 2006, Dr. Willerslev and Kurt Kjaer, a geoscientist at the University of Copenhagen, tried to defy the odds in northern Greenland.

但在2006年，威勒斯列夫博士和哥本哈根大学的地球科学家库尔特·克亚，试图在格陵兰岛北部挑战这种可能性。

They made their way to a geological formation called Kap Kobenhavn, a series of bare hills as desolate as a moonscape. Previously, scientists had found plant fossils there that they estimated to be 2.4 million years old.

他们来到了一个名为Kap Kobenhavn的地质构造，这是一些如月球表面般荒凉的光秃秃的小山。此前，科学家在那里发现了植物化石，他们估计这些化石有240万年的历史。

Finding DNA in the sediments would have been astonishing. "If you want to move things forward, you need to take some leaps," Dr. Kjaer said.

在这些沉积物中发现DNA将是令人震惊的。"如果想让事情向前发展，那就需要跳几步。"克亚博士说。

The researchers dug up permafrost and brought it back to Copenhagen to search for DNA. They failed to find any. In later years, Dr. Willerslev and his colleagues had more success when they examined younger sediments and bones from other parts of the world.

研究人员挖出了永久冻土，并将其带回哥本哈根寻找DNA。他们一无所获。在后来的几年里，威勒斯列夫博士和他的同事们在研究世界其他地区较为晚期的沉积物和骨骼时取得了更大的成功。

They discovered a wealth of ancient human DNA that has helped reshape our understanding of our species' history.

他们发现了丰富的古人类DNA，帮助我们重塑了对人类历史的理解。

词汇预习

• species [高考]

  美[ˈspiːʃiːz] | 英[ˈspiːʃiːz]

  n. 种类；（单复同）物种

• region [高考]

  美[ˈriːdʒən] | 英[ˈriːdʒən]

  n. 地区；范围；领域；地带；地域

• ecosystem [高考]

  美[ˈiːkoʊsɪstəm] | 英[ˈiːkəʊsɪstəm]

  n. 生态系统

• journal [高考]

  美[ˈdʒɜːrnl] | 英[ˈdʒɜːnl]

  n. 日志；日记；期刊

• coastal [高考]

  美[ˈkoʊstl] | 英[ˈkəʊstl]

  adj. 沿海的；海岸的；沿岸的

• formation [高考]

  美[fɔːrˈmeɪʃn] | 英[fɔːˈmeɪʃn]

  n. 形成；队形；编队；构造；[地]地层

• reshape [高考]

  美[riˈʃep] | 英[ˌri:ˈʃeɪp]

  v. 重新塑造；使成新的形状；改造；打开新局面

• advance [高考]

  美[ədˈvæns] | 英[ədˈvɑːns]

  n. 前进；进展；预付金 v. 前进；预付；增长；推进 adj. 预先的；提前的

• previous [高考]

  美[ˈpriːviəs] | 英[ˈpriːviəs]

  adj. 以前的；先于；在 ... 之前

• bare [高考]

  美[ber] | 英[beə(r)]

  adj. 赤裸的；空的；仅有的；贫瘠的，荒芜的 vt. 使裸露；暴露

• extraordinary [高考]

  美[ɪkˈstrɔːrdəneri] | 英[ɪkˈstrɔːdnri]

  adj. 非凡的；特别的；特派的

• Arctic [高考]

  美[ˈɑːrktɪk] | 英[ˈɑːktɪk]

  adj. 北极的；极寒的 n. 北极圈；北极

• a series of [高考]

  美[ə ˈsɪriːz əv] | 英[ə ˈsɪəriːz ɒv]

  一系列, 一连串

• willow [高考]

  美[ˈwɪloʊ] | 英[ˈwɪləʊ]

  n. 柳树；柳木制品

• would [高考]

  美[wʊd , wəd] | 英[wʊd , wəd]

  aux. 将；可能；大概；总会；愿意；will的过去式

• birch [四级]

  美[bɜrtʃ] | 英[bɜ:tʃ]

  n. 桦树；桦木；用桦条抽打 v. 用桦条抽打

• look at [四级]

  美[lʊk æt] | 英[lʊk æt]

  （仔细地）看；着眼，考虑

• offering [四级]

  美[ˈɔːfərɪŋ] | 英[ˈɒfərɪŋ]

  n. 供品；作品；出售物

• odds [四级]

  美[ɑːdz] | 英[ɒdz]

  n. 机率；可能性；差别；投注赔率；让步；优势

• frustrating [四级]

  美[ˈfrʌstreɪtɪŋ] | 英[frʌˈstreɪtɪŋ]

  adj. 使人沮丧的；令人泄气的

• defy [六级]

  美[dɪˈfaɪ] | 英[dɪˈfaɪ]

  vt. 藐视；挑衅；反抗

• desolate [六级]

  美[ˈdesələt , ˈdesəleɪt] | 英[ˈdesələt , ˈdesəleɪt]

  adj. 荒凉的；荒芜的；孤单寂寞的

• out of [六级]

  美[aʊt ʌv] | 英[aut ɔv]

  prep. 离…一段距离；从…里；离开 ...；出于

• chunk [六级]

  美[tʃʌŋk] | 英[tʃʌŋk]

  n. 大块，厚块；大量，大部分；〈语言学〉话语组成部分，组块；矮胖的人或物 vt. （高尔夫球）没击中 vi. 发出猛冲的声音

• poplar [专八]

  美[ˈpɑplə(r)] | 英[ˈpɒplə(r)]

  n. 白杨；白杨木

• horseshoe [专八]

  美[ˈhɔːrʃʃuː] | 英[ˈhɔːsʃuː]

  n. 马蹄铁；U形物；马蹄形 v. 装马蹄铁

• mammoth [专八]

  美[ˈmæməθ] | 英[ˈmæməθ]

  adj. 巨大的；庞大的 n. 长毛象；猛犸

• geological [考研]

  美[ˌdʒiːəˈlɑːdʒɪkl] | 英[ˌdʒiːəˈlɒdʒɪkl]

  adj. 地质学的

• Christ [考研]

  美[kraɪst] | 英[kraɪst]

  n. 基督；救世主 int. 天啊！

• caribou [托福]

  美[ˈkærəˌbu] | 英[ˈkærɪbu:]

  n. 北美驯鹿

重点讲解

Oldest Known DNA Offers Glimpse of a Once-Lush Arctic

从已知最古老的DNA中窥见曾经郁郁葱葱的北极

lush   adj. 草木繁茂的；鲜嫩葱翠的

【例】the lush green countryside 草木葱郁的乡村

fragment    n. & v.

1. 作名词：碎片；片段

【例】fragments of glass/conversation  玻璃碎片/谈话的只言片语

2. 作动词：碎裂；破裂

【例】The vase fell and fragmented into small pieces. 

花瓶掉下, 摔成碎片.

【拓展】fragmented  adj. 四分五裂的

【例】a fragmented world 一个四分五裂的世界

In the permafrost at the northern edge of Greenland, scientists have discovered the oldest known fragments of DNA, offering an extraordinary look at an extraordinary ancient ecosystem.

在格陵兰岛北部边缘的永久冻土中，科学家们发现了已知最古老的DNA片段，让人们难得看到了一个不同寻常的古代生态系统。

lush   adj. 草木繁茂的；鲜嫩葱翠的

【例】the lush green countryside 草木葱郁的乡村

fragment    n. & v.

1. 作名词：碎片；片段

【例】fragments of glass/conversation  玻璃碎片/谈话的只言片语

2. 作动词：碎裂；破裂

【例】The vase fell and fragmented into small pieces. 

花瓶掉下, 摔成碎片.

【拓展】fragmented  adj. 四分五裂的

【例】a fragmented world 一个四分五裂的世界

The genetic material dates back at least two million years -- that's nearly twice as old as the mammoth DNA in Siberia that held the previous record.

这种遗传物质至少可以追溯到200万年前----比此前纪录保持者西伯利亚猛犸象的DNA要古老一倍。

date back/date back to    追溯到；始于

（英文释义：to have existed since a particular time in the past or for the length of time mentioned）

【例】The custom dates back hundreds of years. 

这一习俗可以追溯到几百年前。

The college dates back to medieval times. 

这所学院创办于中世纪。

【拓展】date from  始于；从……至今

【例】This church dates from the 6th century. 

这座教堂早在6世纪就建成了。

And the samples, described on Wednesday in the journal Nature, came from more than 135 different species. Together, they show that a region just 600 miles from the North Pole was once covered by a forest of poplar and birch trees inhabited by mastodons.

这些样本来自超过135个不同的物种，在周三的《自然》期刊上进行了描述。它们共同表明，距离北极仅600英里的一个地区曾经被白杨树和桦树森林所覆盖，这里也曾是乳齿象的栖息地。

inhabit   v. 居住在；栖息于

【例】Several hundred species of birds inhabit the island.

数百种鸟类栖息在这个岛上。

Love is composed of a single soul inhabiting two bodies.

爱情是在两个不同的身体里住着同一个灵魂。

【拓展】inhabited  adj. 有人居住的    uninhabited  adj. 无人居住的

habitat  n. （动植物的）栖息地    inhabitant  n. 居民；（栖息的）动物

The forests were also home to caribou and Arctic hares. And the warm coastal waters were filled with horseshoe crabs, a species that today cannot be found any farther north of Maine. Independent experts hailed the study as a major advance.

这些森林也是驯鹿和北极野兔的家园。温暖的沿海水域充满了马蹄蟹，这一物种如今在缅因州以北的地方已难寻踪迹。独立专家称赞这项研究是一项重大进步。

hail   v. 

1. 赞颂；赞扬

【例】The conference was hailed as a great success. 

会议被称颂为一次巨大的成功。

2. 打招呼；招手示意

【例】to hail a taxi/a friend across the street/hail it  叫出租车/向街对面的朋友打招呼/（向飞船）打招呼

3. 欢呼；喝彩

【例】The crowd hailed the actress with joy. 

人群兴高采烈地向那位女演员欢呼。

"It feels almost magical to be able to infer such a complete picture of an ancient ecosystem from tiny fragments of preserved DNA," said Beth Shapiro, a paleogeneticist at the University of California, Santa Cruz.

"从保存下来的DNA微小片段中推断出一个古老生态系统的完整图景，这让人感觉很神奇。"加州大学圣克鲁斯分校的古遗传学家贝丝·夏皮罗说。

blow one's mind   使某人兴奋（或吃惊）

（英文释义：to produce a very strong pleasant or shocking feeling）

【例】There was one scene in the film that really blew my mind. 

电影里有一幕真的让我感到极度兴奋。

【拓展】mind-blowing  adj. 非常令人兴奋的；非常令人吃惊的

【例】The movie's special effects are mind-blowing.

电影的特效极其震撼。

"I think it's going to blow people's minds," said Andrew Christ, a geoscientist at the University of Vermont who studies the ancient Arctic. "It certainly did so for me."

"我认为这会让人们大为震惊。"佛蒙特大学研究古代北极的地球科学家安德鲁·克罗斯说，"反正已经让我感到吃惊了。"

blow one's mind   使某人兴奋（或吃惊）

（英文释义：to produce a very strong pleasant or shocking feeling）

【例】There was one scene in the film that really blew my mind. 

电影里有一幕真的让我感到极度兴奋。

【拓展】mind-blowing  adj. 非常令人兴奋的；非常令人吃惊的

【例】The movie's special effects are mind-blowing.

电影的特效极其震撼。

The discovery came after two decades of scientific gambles and frustrating setbacks.

这一发现是历经了二十年的科学赌博和令人沮丧的挫折之后取得的。

setback   n. 

1. 挫折；阻碍

【例】suffer a setback in one's business  某人生意上遇到挫败

2. 病情反复

【例】The patient had a setback in his recovery. 

病人在康复过程中病情又有了反复。

【拓展】set sb/sth back  使延误；推迟

【例】The bad weather set back the building program by several weeks. 

天气恶劣，建筑计划延误了几个星期。

One of the leaders of the project, Eske Willerslev, pioneered methods for pulling DNA out of sediment while he was a graduate student at the University of Copenhagen.

该项目的领导者之一埃斯克·威勒斯列夫在哥本哈根大学读研究生时，就开创了从沉积物中提取DNA的方法。

pioneer   n. & v.

1. 作名词：先锋；先驱

【例】a pioneer in the field of microsurgery 显微外科领域的创始人

2. 作动词：开创；做先锋

【例】pioneer the manned exploration of space 首次进行载人的宇宙空间探索

【拓展】pioneering   adj. 开拓性的；先驱性的

In 2003, studying a chunk of Siberian permafrost, he and his colleagues found DNA from plants such as willow and daisies dating 400,000 years ago. That discovery set a record for the oldest DNA, and many scientists doubted it would be possible to find anything much older.

2003年，在研究西伯利亚的一大块永久冻土时，他和同事们发现了40万年前柳树和雏菊等植物的DNA。这一发现创造了最古老的DNA纪录，许多科学家怀疑是否有可能发现更古老的东西。

pioneer   n. & v.

1. 作名词：先锋；先驱

【例】a pioneer in the field of microsurgery 显微外科领域的创始人

2. 作动词：开创；做先锋

【例】pioneer the manned exploration of space 首次进行载人的宇宙空间探索

【拓展】pioneering   adj. 开拓性的；先驱性的

But in 2006, Dr. Willerslev and Kurt Kjaer, a geoscientist at the University of Copenhagen, tried to defy the odds in northern Greenland.

但在2006年，威勒斯列夫博士和哥本哈根大学的地球科学家库尔特·克亚，试图在格陵兰岛北部挑战这种可能性。

defy   v. 

1. 违抗；反抗；蔑视

【例】I wouldn't have dared to defy my teachers. 

我可不敢不听老师的话。

2. 使成为不可能

【例】to defy explanation/description/categorization 无法解释/描述/分类

3. 经受得住；顶住；抗住

【例】He was going ahead defying all difficulties. 

他顶住一切困难，坚持干下去。

odds   n. 

1. （事情发生的）可能性，几率

【例】The odds are that she'll win. 

她有可能会赢。

The odds are very much in our favour/heavily against us. 

我方胜算/失败的几率极大。

2. 不利条件；逆境

【例】They secured a victory in the face of overwhelming odds. 

尽管情况非常不利，他们仍得到了胜利。

【辨析】odd  adj. 奇怪的；偶然出现的

They**** made**** their way to**** a geological**** formation called**** Kap Kobenhavn,**** a series**** of**** bare**** hills as**** desolate**** as**** a moonscape.**** Previously****,**** scientists**** had found plant fossils there that**** they**** estimated to**** be**** 2.4 million years old.****

他们来到了一个名为Kap Kobenhavn的地质构造，这是一些如月球表面般荒凉的光秃秃的小山。此前，科学家在那里发现了植物化石，他们估计这些化石有240万年的历史。

Finding DNA in the sediments would have been astonishing. "If you want to move things forward, you need to take some leaps," Dr. Kjaer said.

在这些沉积物中发现DNA将是令人震惊的。"如果想让事情向前发展，那就需要跳几步。"克亚博士说。

leap  v. & n. 

1. 作动词

（1）跳跃

【例】A dolphin leapt out of the water. 

海豚跃出水面。

（2）猛冲；突然做

【例】They leapt into action immediately. 

他们立即断然采取了行动。

2. 作名词：跳跃；飞跃

【例】That's one small step for man, one giant leap for mankind.

这是个人的一小步，人类的一大步。

Few people successfully make the leap from television to the movies. 

从电视业转向电影业很少有人成功。

The researchers dug up**** permafrost**** and brought it**** back**** to**** Copenhagen**** to**** search**** for DNA.**** They**** failed**** to**** find**** any.**** In**** later years,**** Dr****.**** Willerslev**** and his colleagues**** had more**** success when**** they**** examined**** younger sediments and bones from**** other parts of**** the world.****

研究人员挖出了永久冻土，并将其带回哥本哈根寻找DNA。他们一无所获。在后来的几年里，威勒斯列夫博士和他的同事们在研究世界其他地区较为晚期的沉积物和骨骼时取得了更大的成功。

They discovered a wealth of ancient human DNA that has helped reshape our understanding of our species' history.

他们发现了丰富的古人类DNA，帮助我们重塑了对人类历史的理解。

a wealth of   大量的；丰富的

【例】The new manager brings a great wealth of experience to the job. 

新任经理为这项工作带来了丰富的经验。

课后练习

• What can be learned about the DNA fragments discovered in Greenland?

  A. They demonstrate the vulnerability of the ecosystem.

  B. They offer clues of the ancient Arctic environment.

  C. They contain information of mammoth in Siberia.

  D. They reveal the reasons of extinction of some species.

• The DNA fragments show that a region near the North Pole ____.

  A. suffered from a natural disaster

  B. needed protection and conservation

  C. was inhabited by a diversity of species

  D. was endowed with abundant resources

• Dr. Willerslev went to Kap Kobenhavn to ____.

  A. test his methods of extracting DNA from sediment

  B. study the genetic evolution of ancient plants

  C. break the record by searching for the oldest DNA

  D. advance his understanding of DNA in fossils

• Dr. Willerslev succeeded in ____.

  A. discovering DNA in the permafrost of Kap Kobenhavn

  B. estimating the history of the plant fossils in Greenland

  C. formulating a theory of the development of human species

  D. finding numerous ancient human DNA outside Greenland