I have a black back female normal that I bred to a black back cinnie and produced black back cinnies and black back normals. So at the very least, the offspring are genetic. I'll have to breed both of them to other animals this season to see if they both are genetic or if just one of them was the dominant one.

Here are pictures of them and their babies.

Black back cinnie:



Black back normal:



Babies:





One of the black back normals: