If Homo sapiens and Neanderthals are different species, how did they interbreed and produce the fertile offspring needed for modern humans to have some Neanderthal DNA?

Question

I was told that two seperate species couldn’t interbreed and produce fertile offspring, so I don’t understand how we ended up with some Neanderthal DNA.

In: Biology

Answer 1

Two different separate species cannot. But similar animals can. For example, you can mate some wild felines with domestic felines.

So the theory is that the early proto humans were close enough in DNA that they could mate. Its very possible that mating wasn’t successful all the time, but enough of the time for the genes to mix. And as they mixed, it would make sense that more and more compatibility would develop.

Would be more like breeding different dog breeds than completely separate species.