In reply to nastyned:
> I know it would take a while, and be unethical and immoral, but as many people have 1-4% of the genome originating from neanderthals would it be possible to selectively breed neanderthals back into existence?
Unlikely to be possible. Because of the way population genetics works over those sorts of time-scales, that 1-4% will not be randomly sampled from the neanderthal genome. Some portions of the genome will be common, and some will be missing entirely.
This paper suggests that only 20% of an entire neanderthal genome has survived to the present-day.
https://science.sciencemag.org/content/343/6174/1017