 The exact line of descent between domestic sheep and their wild ancestors is unclear . The most common hypothesis states that Ovis aries is descended from the Asiatic ( O. orientalis ) species of mouflon . It has been proposed that the European mouflon ( O. musimon ) is an ancient breed of domestic sheep turned feral rather than an ancestor , despite its commonly being cited as ancestor in past literature . A few breeds of sheep , such as the Castlemilk Moorit from Scotland , were formed through crossbreeding with wild European mouflon . 
