Scientists uncovered genetic traces of Neandertals and Denisovans by screening cave dirt for DNA.
科学家通过扫描洞穴泥土中的DNA发现了尼安德特人和丹尼索瓦人的基因踪迹。
撰文/播音：克里斯托弗·因塔利亚塔(Christopher Intagliata)
翻译：路识宇
审校：杨枭
Fossilized skulls and skeletons found in European caves gave us our first glimpse of our ancient cousins, the Neandertals. And a finger bone, found in a Siberian cave, first indicated the existence of another relative—the Denisovans. But fossils are hard to come by. So here's another option: analyze cave floors to see if it contains any DNA.
在欧洲洞穴中发现的头骨和骨骼化石让我们首次见到了人类的古老表亲——尼安德特人。最近在西伯利亚的一个洞穴中发现的一根手指骨头，又首次指出了我们另一个亲属的存在——丹尼索瓦人。但由于化石很难发现，因此人们想出了另外一个办法：分析洞穴地面，看看它是否含有DNA。
"We find ancient hominins, we find Neandertal mitochondrial DNA, and Denisovan mitochondrial DNA."
“我们发现了古代人类，因为我们发现了尼安德特人的线粒体DNA和丹尼索瓦人的线粒体DNA。”
Viviane Slon, a geneticist at the Max Planck Institute in Germany.
维维恩·斯隆（Viviane Slon）是德国马克斯·普朗克研究所的遗传学家。
She and her team found that molecular evidence by testing teaspoonfuls of sediment from seven different caves. And they screened specifically for mitochondrial DNA—because there's a lot more copies of it in cells compared to nucleus DNA, which has just one set per cell.
她和她的团队一匙接一匙地检测了七个不同的洞穴中的沉积物，最终发现了分子证据。他们专门针对线粒体DNA进行扫描检测——因为与细胞核相比，每个细胞中会有更多线粒体，而每个细胞只有一个核。
The researchers uncovered genetic evidence of Denisovans where you might expect—at Denisova Cave in Siberia. Which showed that their strategy was sound. They found Neandertal DNA there too, and at three of the other seven caves—including a cave where no Neandertal fossils have ever been found, only artifacts and animal bones. And they found the DNA of some surprise guests, too: "The woolly mammoth, or the woolly rhino. We have cave hyenas and cave bears." The study is in the journalScience. [Viviane Slon et al., Neandertal and Denisovan DNA from Pleistocene sediments]
不出所料，研究人员在西伯利亚的丹尼索瓦洞穴发现了丹尼索瓦人的基因证据。这就证明了他们的方法是有效的。他们还在七个洞穴的三个洞穴里发现了尼安德特人的 DNA——包括一个没有发现尼安德特人化石的洞穴，那里面只有手工制品和动物骨骼。他们还发现了一些预料之外的DNA：“猛犸象，也有可能是披毛犀。我们还找到了鬣狗和熊的洞穴。”这项研究刊登在Science杂志上。
This preliminary success, Slon says, means the method could be a good complement to traditional surveys. "We're not trying to replace working on ancient DNA from fossils, but rather open all the archaeological sites where there are no hominid fossils for genetic analyses." Leading, hopefully, to a broader census of our ancient relatives. No bones about it.
斯隆表示，研究的初步成功意味着该方法可能是对传统调查的良好补充。“我们不是要取代通过化石分析古代DNA的方法，而是想使得那些没有发现人科化石的考古遗址也能够进行遗传分析。”希望能通过这种方式，在没有骨头的情况下，我们也可以对远古的亲戚进行更广泛的调查。
—Christopher Intagliata
https://www.scientificamerican.com/podcast/episode/ancient-human-dna-found-in-cave-dirt/
