Leopard Complex - The Lp Gene

The Lp Gene

Although the spotting and roaning patterns that make up the leopard complex sometimes appear very different from each other, the ability of leopard-spotted horses to produce the full spectrum of patterns, from mottled skin to roaning to more leopard-spotted offspring, has long suggested that a single gene was responsible. This gene was termed Lp for "leopard complex" by Dr. D. Phillip Sponenberg in 1982, and was described as an autosomal, incomplete dominant gene. Horses without the gene (lplp) were solid-colored, those with two copies of the gene (homozygous or LpLp) were usually "fewspots", while those with a single copy of the gene (heterozygous or Lplp) ranged from mere mottled skin to full leopard.

In 2004, Lp was assigned to equine chromosome 1 (ECA1) by a team of researchers. Four years later, this team mapped the Lp gene to a transient receptor potential channel gene, TRPM1 or Melastatin 1 (MLSN1). As yet, the etiology of this condition remains poorly understood.

In 2011, it was announced that an allele associated with Lp was identified in DNA samples collected from prehistoric horses. This finding represents evidence for the presence of leopard complex spotting in prehistoric wild horse populations. The ancient origin of the allele may explain the presence of spotted horse paintings in paleolithic cave art.