Red 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 PtWU (or) PtPt (but not) PtPt WU. They could also be nn for the series, and have no markings here.
Red Unders genes are codominant, meaning having more than one different type will show the effects of both.
However, having duplicates, like two copies of Pt, will not create two different types of Points.
Red based, affected by any genes that target red, such as axanthic
Red markings which typically cover the face and neck. It may spread to legs, underbelly, and rump. May create a dorsal stripe.
Can be bright red to liver in hue - may even appear black
May have a slight gradient.
Skin is not affected. Eyes are not affected.
In hooved creatures, mane and tail are affected where marking touches.
Compare to: Elk, Scimitar Oryx