Zebra Stripes?

Does anyone know how zebra stripes show up in their genes?

I don't know a whole lot, but I know dun horses get the striping like that. I think it's pretty cool. Pretty soon the people who know more about colors/genetics will chime in and can tell you more :)

It's leg barring, which is also called zebra barring. It's one of the primitive markings that are put on a horse by the dun gene. The other primitive markings are cobwebbing on the face, a dorsal stripe, and shoulder barring.

Like Po said, it is most often caused by the dun gene, though there are some horses that exhibit some leg barring with nothing more than the sooty gene.