Heritability of traits is a really messy and difficult problem. Sere, you can breed tameness into wild foxes, but that doesn't mean you can easily breed more ta

Heritability of traits is a really messy and difficult problem. Sere, you can breed tameness into wild foxes, but that doesn't mean you can easily breed more tameness into already tame foxes/dogs. There might be some low-hanging fruit that's easy to exploit and after that, it's mostly random chance and the environment that determines things. But that again depends on what the environment is like - if all dog owners routinely raise their puppies in the same extreme way, their inherited differences might either be invisible because none get the chance to express them, or even more significant because that's the only factor left that can sort out how they respond to their environment.