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Along the way, the researchers tweaked their methods for extracting DNA from ancient samples and upgraded the machines they used to sequence it.
在此过程中，研究人员调整了从古代样本中提取DNA的方法，并升级了用来对其测序的机器。
As they became better at fishing for genes, they would take out more of the Kap Kobenhavn samples for another shot. But for years they failed, again and again.
随着他们在寻找基因方面更得心应手，他们取出更多的Kap Kobenhavn样本进行另一次尝试。但多年来，他们失败了一次又一次。
From time to time they were tantalized by what looked like short bits of DNA, which are called reads.
有很多次，他们被看起来像短小DNA片段的物质所戏弄，这些物质叫读长。
The researchers couldn't rule out the possibility that bits of young DNA in Greenland, or even in their lab, had contaminated the reads.
研究人员不能排除来自格陵兰岛，甚至是来自他们实验室的晚期DNA片段已经污染了读长的可能性。
Finally, after a major upgrade in their technology, they found DNA in the samples in 2017. The permafrost turned out to be loaded with genetic material. Before long they had collected millions of DNA fragments.
最后，在他们的技术进行了一次重大升级后，2017年他们在样本中发现了DNA。这些永久冻土中原来含有大量遗传物质。不久，他们就收集了数百万个DNA片段。
"It was a breakthrough," Dr. Willerslev said. "It was going from nothing or very little that you don't know is real, to suddenly: It's there."
"这是一个突破，"威勒斯列夫博士说，"从什么都没有或者只有很少难辨真假的东西，突然变成了：它就摆在你面前。"
The researchers lined up the fragments with DNA sequences of living species to figure out where they belonged on the evolutionary tree.
研究人员将这些片段与现存物种的DNA序列比对，以确定它们在进化树上的位置。
They found 102 different kinds of plants--including 78 that had previously been identified from fossils and 24 new ones. The plant DNA painted a picture of forests dominated by poplar and birch trees.
他们发现了102种不同的植物，其中包括78种以前从化石中发现的植物和24种新的植物。植物DNA描绘了一幅以白杨树和白桦树为主的森林图景。
Other sequences come from land animals, including caribou, hares, mastodons, geese, lemmings and ants. The researchers also found marine species, such as horseshoe crabs, corals and algae.
其他序列来自陆地动物，包括驯鹿、野兔、乳齿象、鹅、旅鼠和蚂蚁。研究人员还发现了海洋物种，如马蹄蟹、珊瑚和藻类。
"It superseded everything we imagined," Dr. Kjaer said.
"它取代了我们之前想象的一切。"克亚博士说。
The researchers also searched the permafrost for new clues to the age of the fossils. They found layers in the sediment in which the minerals revealed that the Earth's magnetic field had flipped.
研究人员还在永久冻土中寻找化石年代的新线索。他们在沉积物中发现了几层矿物质，揭示地球磁场曾经发生了翻转。
The age of those reversals helped the researchers determine that Kap Kobenhavn was at least two million years old, but they could not establish a clear upper limit. "My gut feeling as a geoscientist is that it's older," Dr. Kjaer said.
这些逆转发生的年代帮助研究人员确定，Kap Kobenhavn至少有200万岁，但他们无法确定一个明确的上限。"作为一名地球科学家，我的直觉是它还要更加古老。"克亚博士说。
The researchers ruled out the possibility that the DNA came from younger species that contaminated the older permafrost.
研究人员排除了这些DNA来自较晚期的物种，而这些物种污染了较古老的永久冻土的可能性。
The DNA of the birch trees lacked many of the mutations that living species have, indicating that they were ancient. The DNA also had a distinct pattern of damage that occurs only when the molecules have been sitting in sediment for geological stretches of time.
白桦树的DNA缺乏许多现存物种所具有的突变，这表明它们是古老的。这些DNA也有一种明显的损伤模式，只有当分子在沉积物中停留几段地质时期才会发生。
"It really helps show that this really is old DNA," said Tyler Murchie, a postdoctoral researcher at McMaster University who was not involved in the new study.
没有参与这项新研究的麦克马斯特大学博士后研究员泰勒·默奇说："这真的有助于证明这确实是古老的DNA。"
