By Patty Wilber
One of the fun features of the Appaloosa breed is the fact that the coat color can really change over time due to the progressive depigmenting effects of the LP gene, which can result in a coat pattern referred to as “varnish roan”. Vanish roan is not the same as a gray and is not the same as a true roan either.
Lucy has two copies of the LP gene (LP/LP). She started off solid red with white on her hip. She had roaned out significantly by age one. Here she is at six, looking like a typical (but extra cute) varnish roan. She does not have any spots, which is characteristic of LP/LP horses.
Gette has just one copy of the LP gene (LP/lp). She will also develop a varnish roan pattern, but probably more slowly than Lucy. Also, Gette has spots, which is common for the LP/lp horses. These will become more prominent as she roans, at least for a while, but may fade as she ages.
Now it is June 2022, and Gette has shed her winter coat. She is much lighter and her spots are easy to see. Her tail is graying out. Her mane is still thick and black, but it may thin out significantly if (when?) it depigments. We will see!
Neither Lucy, nor Gette have the PATN1 gene which modifies the LP gene. Some examples are shown below. Figure from UCDavis.
Of course, I will keep taking pictures of Gette each summer and document the changes!