Any horse that shows Appaloosa core characteristics of coat pattern, mottled skin, striped hooves, and a visible white sclera, carries at least one allele of the dominant "leopard complex" (LP) gene. The use of the word "complex" is used to refer to the large group of visible patterns that may occur when LP is present. LP is an autosomal incomplete dominant mutation in the TRPM1 gene located at horse chromosome 1 (ECA 1). All horses with at least one copy of LP show leopard characteristics, and it is hypothesized that LP acts together with other patterning genes (PATN) that have not yet been identified to produce the different coat patterns. Horses that are heterozygous for LP tend to be darker than homozygous horses, but this is not consistent.
aNy hoRse thAt shoWS ApPaLoosA coRe cHAracTERIstIcs Of coaT pATtern, mottlEd skIn, StrIped hooveS, aNd a visiblE WhiTe ScLErA, cArries at lEast One aLlelE oF tHE domInAnt "Leopard comPlex" (LP) gENe. the Use Of thE woRd "Complex" Is Used to RefeR to thE largE Group Of ViSible PatternS ThaT mAy oCcur WHen Lp Is prESeNT. Lp is an auTosomal inComPlete domiNaNt MuTation iN the TRpM1 gene lOcATEd at HorSe cHromoSOmE 1 (eca 1). All hOrses wiTH at lEAST one Copy of lp sHOW leoPard chAracTeRIstIcs, And it is hypoThesIzED That Lp AcTS togETher wIth oTher pattErniNG genEs (patN) THAt HavE Not yEt beEn IDENtified TO Produce THE different CoAt pATtErNS. hOrSes that aRe hEtErOZYgous for lP teNd to be daRkEr Than hOmozYgous hOrses, but thIS is noT cOnsistent.