Neanderthal genome 'spread' looks like the same 'spread' of matching DNA to Ghengis Khan. And the fact that Neanderthal DNA was found as far away as China & New Guinea, I would surmise that Neanderthal could have originated in THAT area. Just because a skeleton hasn't been found doesn't mean its not so. But it makes more sense to the data research when combined with the DNA research which has been done which proved the relationship to Ghengis Khan.