In his own words P Sponenberg
http://www.soaysheepbreeders.com/reports/sponenberg060410.pdf The main mechanism for color variation is the Agouti locus (locus is Greek for address, and just
means a specific site), which controls the distribution of light (white to tan) and dark fibers (black
to brown) over the body of the animal. The Agouti patterns in the Soay are limited to two
choices. The first of these is the common and familiar “Soay pattern”, which results in a dark
sheep with lighter tan trim on the belly, legs, over the eyes, and the muzzle. The naming of this
pattern is somewhat controversial. Some experts consider that this is analogous to the wild type
pattern in sheep, or Mouflon pattern. I think that the Soay pattern is much more like the
black and tan pattern, with a generally black top and the light trim. Whatever the truth is, the controversy can somewhat be avoided by referring to this distinctive pattern as “Soay.”