Remember, they produce fertile offspring when interbred.
But they don't interbreed unless a person intervenes.
A wolf does with a dog. The wolf is a wild, untameable dangerous animal, a dog can be tamed.
Ignoring for the moment that a wolf is basically a wild dog, again they only breed when man intervenes. Dogs wouldn't exist at all without man's intervention.
So that means, character traits are also inheritable, within one species. Well...
Weird logic jump, but yes, character traits are heritable. Humans haven't been selectively bred by a weird outside force who wants a docile animal with a smooshed up face and breathing trouble. Humans quite obviously inherit their character traits from their parents. But if you take your typical brown American, they probably have European, native American, and African ancestry. Maybe some Asian. How the hell are you going to classify that person, let alone try to correlate their inherited skin color to their inherited personality? A classification system that cannot classify the President (or nearly 1/3 of the US) is pretty useless.