Sierra is a daughter of the young smoky black stallion, DM Prairie Smoke'N, also featured on the "Look-A-Like" page. Her dam is a very dark brown mare, with no "color" lines.

If Sierra were a brown dun, she would have been born looking very similar to a bay dun, with body coat having a caramely-red tone. Instead, Sierra has the typical creamy-gold tones of the cream gene on bay or brown foal based color.

Sierra's dorsal, and wither and neck markings are very common especially on brown based foals, as it is the beginnings of the brown agouti gene "caping" over the top line. These markings can also be found on non-brown based foals and adults as well due to counter shading and seasonal sooty.

The masking on Sierra's face is another trademark of the brown agouti pattern. It is not dun face masking. Unlike masking from the brown agouti gene, which capes down from the top of the head/face, dun face masking only appears low on the nose, just above the nostrils.