Black Unders genes all attach to the same area, creating a series. Creatures can only have two genes in a series at most, one inherited from each parent.
So they could, for example, be MaD (or) MaMa (but not) MaMa/D. They could also be nn for the series, and have no markings here.
Black Unders Series genes are codominant, meaning having more than one different type will show the effects of both.
However, having duplicates, like two copies of Ma, will not create two different types of Mask.
Black based, affected by any genes that target black such as merle
Black belly stripe, ranging from dark to extremely faded and thick to very thin.
Can spread over flank, down legs, and create a dorsal stripe on the topline and down the chest. May leave gaps.
Makes a mask on face spreading from nose bridge and jaw, which may cover the entire face.
If Plains Unders is present, tends to align itself with the edges of this marking, creating borders around it.
Skin is not affected. Eyes are not affected.
In hooved creatures, mane and tail are black where marking touches.
Compare to: Gemsbok, Arabian Oryx
NOTE: The following examples also display Plains Unders, creating white on the face. Oryx Unders by itself would cause an entirely black face.