在现代西非人的DNA中，发现了一种不为人知的已灭绝人类的“幽灵”

在现代西非人的DNA中，发现了一种不为人知的已灭绝人类的“幽灵”

The gene pool of modern West Africans contains the 'ghost' of a mysterious hominin, unlike any we've detected so far. Similar to how humans and Neanderthals once mated, new research suggests this ancient long-lost species may have once mingled with our ancestors on the African continent.

现代西非人的基因库中含有一种神秘古人类的“幽灵”，这与我们迄今为止发现的任何古人类都不同。类似于人类和尼安德特人曾经的交配方式，新的研究表明，这一消失已久的古老物种可能曾经与我们在非洲大陆的祖先交配过。

Using whole-genome data from present-day West Africans, scientists have found a small portion of genetic material that appears to come from this mysterious lineage, which is thought to have split off from the human family tree even before Neanderthals.

利用现代西非人的全基因组数据，科学家们发现了一小部分遗传物质，似乎来自这个神秘的世系，这个世系被认为早在尼安德特人之前就从人类的族谱中分离出来了。

Today, it's thought (although still being debated) that anatomically modern humans originated in Africa, and that once these populations migrated to Europe and Asia, they interbred with closely-related species like Neanderthals and Denosovans.

今天，人们认为(尽管仍在争论中)，从解剖学上讲，现代人类起源于非洲，一旦这些种群迁移到欧洲和亚洲，他们就会与尼安德特人和德诺索瓦人等亲缘关系很近的物种杂交。

As such, modern West Africans, like populations in Yoruba and Mende, do not possess genes from either of these ancient species, but that doesn't mean there was no intermixing. In fact, recent evidence suggests the genetic past of West Africans may contain a similarly juicy narrative.

因此，现代西非人，就像约鲁巴人和门德人一样，并不拥有这两种古老物种的基因，但这并不意味着没有混合。事实上，最近的证据表明，西非人的遗传历史可能包含着类似的有趣故事。

The idea is hard to confirm, because ancient human remains and DNA are scarce on the African continent and even harder to find in West Africa.

这一观点很难得到证实，因为在非洲大陆上，古人类遗骸和DNA非常稀少，在西非更难找到。

Fortunately there is one way to get an idea of how ancient humans mixed that doesn't involve studying remains: modern genomics. Researchers decided to compare 405 modern genomes from the Yoruba and Mende populations with genomes from Neanderthals and Denisovans.

幸运的是，有一种方法可以了解古代人类是如何混合在一起的，而不需要研究遗骸:现代基因组学。研究人员决定将约鲁巴人和门德人的405个现代基因组与尼安德特人和丹尼索瓦人的基因组进行比较。

To their surprise, they also found traces of another as-yet-unknown ancient hominin species in their genomes.

令他们惊讶的是，他们还在他们的基因组中发现了另一种尚不为人知的古人类的踪迹。

Similar to how modern humans outside of Africa still hold traces of Neanderthal genes, the authors found populations in West Africa derived between 2 and 19 percent of their genetic ancestry from this as-yet-undiscovered ancient hominin.

类似于非洲以外的现代人仍然保留着尼安德特人的基因痕迹，作者发现西非的人群有2%到19%的遗传祖先来自于这种至今未被发现的古人类。

Interestingly, this isn't the first time 'ghost' species of unknown extinct ancestors have been found in modern DNA. Researchers looking at Eurasian DNA have previously found traces of at least three as-yet-undiscovered ancient hominins in modern human genomes. But this is a first for modern West African DNA.

有趣的是，这并不是第一次在现代DNA中发现已经灭绝的未知“幽灵”物种。研究欧亚人DNA的人员此前在现代人类基因组中发现了至少三种尚未发现的古人类的踪迹。但这是首次发现现代西非DNA。

The study was published in Science Advances.

这项研究发表在《科学进展》杂志上。