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
Turns feet, inner ear, and jaw a shade of red. Can also turn "eyebrows" and the inside of ears red.
May be a very dark red color or so pale it appears white.
May be slightly gradiented.
Skin is not affected. Eyes are not affected.
Compare to: Pointed dogs (rottweiler, doberman), Urajiro dogs (shiba inu, husky, saluki)