I don't think anyone should be surprised that Neanderthal interbred with Denisovan or Sapiens...what is surprising is finding a first generation offspring of such a pairing, that's really finding the proverbial needle in the mother of all haystacks...
I think there was another part that interesting about that find, too. I don't remember it exactly, but it went something like this: The mother was Neanderthal. The father was Denisovan, but had some Neanderthal dna elements that came from a population that was earlier than that of the mother! Thus, the two groups had met at some far earlier time!! That was viewed as countering the idea that one group permanently displaced the other group when they interacted. Whatever. Really interesting!
BTW, fossil AHS go back to 330kya unless that changed recently. That's 120k years further back than previous dates.
Which leads scientists to consider that they are actually looking at a needlestack, and that such hybrids were very common, in certain places and at certain times.
Nice turn of phrase! I'd still suggest it is a matter of a number of needles in a truly enormous haystack, though. Finding this one needle, a child's finger bone, is still pretty clearly difficult.
