Not just Neanderthals: Ghost lineage in Africa left its mark on our DNA

AI 中文解读

人类祖先的“混血史”又添新篇章！科学家在尼安德特人和丹尼索瓦人之外，找到了第三个神秘古人类谱系的遗传痕迹。这个谱系没有留下任何化石或骨骼，却把DNA悄悄融入了我们的基因组，堪称“幽灵家族”。过去我们知道现代人类携带少量尼安德特人基因，但用新分析方法一查，发现还有一部分基因来自更古老的非洲本土长辈。这部分DNA非常隐蔽，就像家族相册里没有照片的远亲，只能从血脉中隐约窥见身影。这项发现改写了人类起源叙事：现代智人在走出非洲之前，就曾与这个神秘群体通婚。对普通人来说，虽然不会立刻改变生活，但它让我们重新认识“我是谁”。祖先的迁徙和交融比想象中更复杂，每个人的基因里都可能藏着一段未被记载的远古浪漫。更关键的是，这些古老基因可能影响免疫系统等健康特征，未来医学研究或许会借此解开某些疾病的遗传谜团。

When the history of our ancestry is written, the fact that we've interbred with some of our closest relatives, the Neanderthals and Denisovans, will have a central role. And it will be tempting to write it as a very tidy story: Once we got genomes from these other groups, it was possible to identify the sequences in our genomes that we shared with them. But in reality, as scientists started poking large enough collections of data, there were regular hints of some strange ancestry in our genomes. It was hard to pin down, though, at least in part because the 2 percent on average of Neanderthal DNA found in many populations does not guarantee that any two individuals will have the same 2 percent. So having the genomes of those two groups made sense of some things researchers had already been seeing. But knowing what we do about Neanderthal and Denisovan DNA is now allowing researchers to answer a somewhat different question: Is there anything else? Using recently developed analytical techniques, they find evidence of a third lineage that we apparently interbred with before any modern humans left Africa. Again, there were hints of this earlier, but so far, there's been no genome from a modern human relative to help us understand the details—the source of this DNA remains a "ghost lineage."Read full article Comments