Grulla
The dun gene is dominant, meaning that the horse only needs one copy for it to be expressed. It dilutes the coat, leaving the points undiluted and comes with primitive markings like stripes on the legs and a dorsal stripe.
Horses with only one copy or none will have one of two genes: nd2 or nd1.
This doesn't make the horses dun but nd1 horses might have primitive markings.
The grulla is a black base plus dun.
