...does this mean that Captain Caveman was my ancestor?
Seriously, kinda cool to have this (nearly) proven, given its been speculated for so long. It'll be interesting to see what the bits of DNA left from them actually do.
As is the case with a lot of DNA, the vast majority of it will be either junk or regulatory functions we don't understand yet. I wouldn't hold my breath waiting for anyone to know what any of it does.
That said, I'm sure within a couple years we'll have a couple people claiming to know something, and the media will hype it beyond belief. But the more media attention a bit of science gets, the faster the facts become fuzzy and then irrelevant.
As for the DNA evidence.... spotty as heck and not as mature a science as many would suggest. I will continue to live with the largely untried hypothesis that interbreeding happened. My reasons for this have little to do with various dodgy examples of paleo-genetic analysis. After all, humans will mate with anything that will stand still long enough. That assessment has stood unaltered for some time, and it will continue to stand as the most behaviorally parsimonious set of circumstances in my opinion, until such time as the evidence is conclusive.
More like the differences between tigers and lions. In the fossil record, it's extremely difficult to tell them apart as well. But they clearly are separate species; they can't interbreed and create fertile offspring, and hybrids never occurred in the wild, even when their ranges overlapped in Central Asia and India in historical times.
Actually, a decent percentage of female lygers and tigons have been fertile. For some reason, we've never really bothered applying everything we've learned about the fallacies of the generally accepted species concept to animals. We've got this species concept we inherited from the Dark Ages that we keep teaching in school because it kinda works a decent chunk of the time for more or less all of the highly visible animals and we don't notice the ubiquitous, even habitual, way everything but animals ignores it almost entirely.
That would involve explaining complicated things to children. Can't allow that.
From another article on Time.com on the same subject:
"Among the challenges were eliminating bacterial and fungal DNA, which accounted for 97% of the genetic material in the samples, and guarding against contamination from the researchers themselves, whose own DNA might be mistaken for Neanderthal."
(emphasis mine)
While non-trivial, that's not insurmountable. You could back check your DNA libraries against each separate human lineage they tested (5 as I recall) and see if there are differences that cannot be accounted for due to contamination from the lineage of the researchers.
This is an example of journalists asking researchers to speculate on possible, but not necessarily probable, mistakes. It is also a go-to statement for scientists who don't want this to be true: "Those guys are doin' it wrong."
