What do you mean by 'directly related'? Do you mean offspring back to parent? Offspring back to grandparent? No relation at all? If no relation at all, why not? Evidence that it is bad for the breed? I am curious
~~McKinsey~~
"Men have forgotten this truth," said the fox. "But you must not forget it. You become responsible, forever, for what you have tamed."
~The Little Prince; Antoine de Saint Exupery