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Scientists discovered the oldest known DNA and used it to study what life was like 2 million years ago in Greenland.
科学家发现了已知最古老的DNA，并用其来研究200万年前格陵兰岛的生活情况。
Today, northern Greenland is an empty, cold area.
如今，格陵兰岛北部是一片空旷、寒冷的地区。
But in the past, it was full of trees, plants, and animals.
但在过去，这里到处都是树木、植物和动物。
Kurt Kjaer of the University of Copenhagen was the study's lead writer.
哥本哈根大学的库尔特·克亚尔是这项研究的主要作者。
He said the research "opens the door into a past that has basically been lost."
他说，这项研究“打开了一扇通往基本上已经消失的过去的大门。”
For the study, researchers examined environmental DNA, also known as eDNA, from soil samples.
在这项研究中，研究人员检查了土壤样本中的环境DNA，也被称为eDNA。
eDNA is the genetic material that organisms put into their surroundings, including hair and waste.
环境DNA指的是生物体放入周围环境的遗传物质，包括毛发和排泄物。
The problem with ancient DNA is that the genetic material breaks down over time, leaving scientists with very small pieces to study.
古代DNA的问题在于，遗传物质会随着时间的推移而分解，留给科学家用作研究的片段非常小。
But, with the latest technology, Eske Willerslev of the University of Cambridge said researchers were able to get genetic information out of the small, damaged pieces of DNA.
但是，剑桥大学的埃斯克·威勒斯列夫表示，借助最新的技术，研究人员能够从受损的DNA小片段中提取遗传信息。
In the study, which appeared recently in the publication Nature, researchers compared the DNA to that of different species, looking for matches.
在最近发表在《自然》杂志上的这项研究中，研究人员将样本DNA与不同物种的DNA进行比对，以寻找匹配的DNA。
The samples came from an area in Peary Land, which is now a cold, empty place.
样本取自皮里地的一个地区，那里如今是一个寒冷、空旷的地方。
But millions of years ago, the area went through a time of strong climate change that sent temperatures way up, Willerslev said.
威勒斯列夫说，但在数百万年前，该地区经历了一段剧烈的气候变化时期，导致气温大幅上升。
Soil and rocks likely built up for tens of thousands of years in the area before the climate cooled and locked the DNA into permafrost.
在气候变冷并将DNA锁在永久冻土中之前，该地区的土壤和岩石可能积累了数万年。
The cold environment helped save the small pieces of DNA — until scientists came along and took the samples out, beginning in 2006.
寒冷的环境帮助保存了小片段的DNA，直到2006年初，科学家到达那里取出了样本。
The researchers said when average temperatures were 11 to 19 degrees Celsius higher than today, the area had an unusual number of plant and animal life.
研究人员表示，当平均气温比今天高11到19摄氏度时，该地区的动植物数量异常多。
And pieces of DNA suggest a mix of Arctic plants with ones that usually grow in warmer climates.
DNA片段表明，北极的植物与通常生长在温暖气候下的植物混合存在。
The DNA also showed the presence of animals including geese, hares, reindeer and lemmings.
DNA还显示了鹅、野兔、驯鹿和旅鼠等动物的存在。
Previously, a dung beetle and some hare remains had been the only signs of animal life in the area, Willerslev said.
威勒斯列夫表示，以前，一只蜣螂和一些野兔遗骸是该地区唯一的动物生命迹象。
The researchers said one big surprise was finding DNA from the mastodon, an ancient species that looked like a mix between an elephant and a mammoth.
研究人员表示，一大惊喜是发现了乳齿象的DNA，乳齿象是一种看起来像是大象和猛犸象的混合体的古老物种。
Mastodon DNA remains have previously been found in forests in North America, a long way away from Greenland.
此前曾在距离格陵兰岛很远的北美森林中发现过乳齿象DNA残骸。
"I wouldn't have, in a million years, expected to find mastodons in northern Greenland," said Love Dalen.
洛夫·戴伦说：“在一百万年里，我从未期望过在格陵兰岛北部发现乳齿象。”
Dalen, who was not involved in the study, is a researcher at Stockholm University.
戴伦没有参与这项研究，他是斯德哥尔摩大学的研究员。
DNA samples also suggest the presence of horseshoe crabs and green algae in the area.
DNA样本还表明，该地区存在鲎和绿藻。
Kjaer explained that nearby waters were likely much warmer back then.
克亚尔解释说，当时附近水域的温度可能更高。
Laura Epp, who was not involved in the study, is an eDNA expert at Germany's University of Konstanz.
劳拉·埃普没有参与这项研究，她是德国康斯坦茨大学的环境DNA专家。
She said, with the available data, it is hard to say for sure whether these species lived side by side, or if the DNA was mixed together from different parts of the landscape.
她说，根据现有的数据，很难确定这些物种是比邻而居还是来自不同地区的DNA混合在一起。
But Epp said this kind of DNA research is valuable to show "hidden diversity" in ancient landscapes.
但埃普说，这种DNA研究对于揭示古代景观中的“隐藏多样性”很有价值。
Willerslev believes that because these plants and animals survived during a time of extreme climate change, their DNA could offer a "genetic roadmap" to help us deal with current warming.
威勒斯列夫认为，因为这些植物和动物在极端气候变化时期幸存下来，所以它们的DNA可以提供一个帮助我们应对当前气候变暖的“基因路线图”。
Stockholm University's Dalen expects ancient DNA research to keep pushing deeper into the past.
斯德哥尔摩大学的戴伦期望古代DNA研究能够继续更深入地探索过去。
"I wouldn't be surprised if you can go at least one or perhaps a few million years further back, assuming you can find the right samples," Dalen said.
戴伦说：“假设你能找到合适的样本，起码你能追溯到一百万年或几百万年前，我对此不会感到惊讶。”
I'm John Russell.
约翰·拉塞尔为您播报。
译文为可可英语翻译，未经授权请勿转载！
