So I've bred mice for awhile now, but there are certain things about mouse genetics that I don't understand. Are certain varieties of mice possible to breed for without actually having mice that are already that variety? I mean, if you do not already have a tan mouse, is there a way to breed for a tan mouse? Do you just breed the mice hoping for some genetic mutation to happen? Also, this may be a weird question, but are the fox and tan traits related in any way? Thank you for reading.