Dun factor genetic testing is now available. Sort of. According to UC Davis, “The specific mutation that causes Dun has not yet been identified, and there is no direct test for the gene. VGL has identified DNA markers associated with Dun that can be used to determine if a horse has the Dun gene and how many copies.” They’re still doing research to pinpoint the exact genes, but this is still an exciting breakthrough. Also check out this article on primitive markings from Dun Central Station.