How do we know that the 1-4% shared DNA between humans today and neanderthals is from inter-species procreation?
I've seen in numerous documentaries about human evolution that roughly 1-4% of DNA between Homo sapiens today and Homo neanderthalensis is from inter-species procreation. How did they rule out that these specific genes were not convergent evolution or shared from an earlier ancestor? That detail is never explained in any of these videos, and I'm sort of curious about it.
Semantics and insults aside, does anyone care to offer an explanation to the spirit of the actual question?