THE APPALOOSA, or LEOPARD COMPLEX
The entire range of Appaloosa patterning is called the "Lp" ("Leopard") complex of genes.
Lp genetics are complicated and not yet fully understood.
More than one gene may be at work in creating the wide range of appaloosa
patterns. The American Appaloosa, a breed originating with the Nez Perce
Indians, is the most well known Lp-colored type of horse in the US, and
Mustangs who exhibit Lp color patterns are generally referred to as
Appaloosas, but genetically, they are Lp's. In addition to Appaloosas, some
Asian horses carry this pattern, as do the Knabstrupper and POA (Pony of the
The Leopard Complex includes a number of patterns, including leopard, blanket, few spot, frosted, snowflake, snow cap,& varnish.
All horses within the Lp Complex of Appaloosa-type coloring have mottled skin that is visible around their eyes, muzzle, and genitals. They have visible eye sclera, giving their eyes a "human" look (some other horses, especially pintos, also have prominent sclera)
Genetics of Appaloosa/Leopard:
Current research indicates that Appaloosa patterns are not caused by a single gene. We refer to the
"Leopard complex", or Lp, as the group of genes that must be responsible for appaloosa patterns, but we don't know what all the genes are or how they work. We know that the leopard appaloosa pattern appears to be dominantly inherited, but we know nothing about the other patterns.
Sheila Archer of The Appaloosa Project writes:
"In June (2003) Dr. Rebecca Terry (originally of the University of Kentucky, now at the University of Tampa) and I discovered the location of the LP gene, the main gene which must be inherited in order for Appaloosa "characteristics", their unique form of roaning, and all other coat patterns to be visible. This master gene is located on equine chromosome 1, and we are now in the process of narrowing down the region so that we can develop an actual test for LP.
We have also gathered significant phenotype evidence pointing to the existence of several important white pattern modifier genes, and are working on a study to isolate the most significant of these.
You will find an overview of our research project at this website: www.theappaloosaproject.org Also, if you would like to ask questions of myself and Dr. Terry, we have been running a moderated internet discussion group since September of last year for breeders and enthusiasts. http://groups.yahoo.com/group/theappaloosaproject/ Our site includes a large photo album section with images illustrating everything we've been able to ascertain to this point. In addition, we have a files section where you can find recent articles by our research team members and other contributors. I welcome you to join us, even if you only wish to read through the archived messages and search for information for your own interest. "
COLOR CHANGES OVER AN APPALOOSA'S LIFETIME
Unlike other "White Patterns" like the various Pinto patterns and Roan, the "LP" Appaloosa coloring often changes color patterning considerably through the horse's lifetime.
A horse born with a spotted blanket over its rump may fade to Varnish Roan or develop into a Leopard Spot Appaloosa. Here's Another Example (click)
Varnish Roans start out as normally colored horses, often with appaloosa spotting. This form of roaning usually shows up as an Appaloosa horse ages, often blurring the Appaloosa markings, just like a paint brush can rub out and blend color spots on a wet canvas.
Similar to, but not the same as, greying, It does not start as early as greying does, and sometimes seems to "spread" from the location of the white in the original Appaloosa markings. Varnish Roan is not caused by the Roan gene, but is part of the Appaloosa complex.
Marble & Frosted are other appaloosa patterns, that look a lot like roan.
Here are some good Appaloosa websites:
PMU mare & foal
Registered Appaloosa PMU foal whose spots are just barely starting to show
Andi Harmon on Ty, a varnish/gray appaloosa
Horse Colors Main Page l Base Colors l l
The Overo Group:
Frame Overo l Sabino l Splashed White l Tovero l How To Tell the Pintos Apart
Overo Lethal White Syndrome
Other Spotting Patterns:
Appaloosa l Tobiano l Pintaloosa