Just when you thought you knew everything there is to know about Neanderthals, Svante Paabo, the Swedish researcher who sequenced the Neanderthal genome, throws in another sequenced ancient hominin.

Speaking at the Biology of Genomes meeting in Cold Spring Harbor last night, Paabo revealed that his group has now sequenced nuclear DNA from a bone fragment found in Denisova Cave in Siberia, thought to belong to an extinct, ancient hominin that branched off from the human family tree about a million years ago. The group reported sequencing the mystery hominin’s mitochondrial DNA in March, but couldn’t draw firm conclusions about its relationship with humans and Neanderthals without its nuclear genome.

The major form of damage that occurs to ancient DNA involves the conversion of the base cytosine to another base, uracil. The trick to sequence it was to basically remove the uracil, cutting the DNA at that spot, then sequence the many short snippets thus produced and line them up.

Comparing the sequence to Neanderthal and human sequences revealed that the Denisova hominin is quite distant from humans, sharing a closer common ancestry with Neanderthals. How far back that split occurred isn’t clear, Paabo says, but the Denisova hominin “did not take part in the gene flow from modern humans.” The hope, of course, is that this is just the start, and that other ancient hominin samples will yield sequences as well.