Ok, so I bred a normal coat/ear black berkshire female that I raised myself with a normal coat/ear black hooded male with a granite-ish stripe and a star in the middle of his forehead.
In the litter there were 7.. but the odd thing is that one of the babies has wavy whiskers (not so curly as a rex) and a patch of rex curls in the middle of his back.
How'd this happen? Rex is dominant.. but this rat doesn't look quite rex.