There are 3 variations (in dogs) on the "S Locus"
s^p which makes piebald, which would resemble our piebald, broken, and even marked mice.
s^i which makes the Irish pattern seen on Aussies, Border Collies, etc. This could easily be bred to resemble Hereford.
s^w which is usually a head marking on each side of the face (over both the eye and ear) and a rump marking, which does resemble the dutch mouse.
Any one of these could be present on the S Locus either together, or paired with another gene from the locus (s^p/s^i or s^p/s^w).
It may very well be the same for mice.
s^p which makes piebald, which would resemble our piebald, broken, and even marked mice.
s^i which makes the Irish pattern seen on Aussies, Border Collies, etc. This could easily be bred to resemble Hereford.
s^w which is usually a head marking on each side of the face (over both the eye and ear) and a rump marking, which does resemble the dutch mouse.
Any one of these could be present on the S Locus either together, or paired with another gene from the locus (s^p/s^i or s^p/s^w).
It may very well be the same for mice.