What is a Homozygous Appaloosa?
Thanks to the work of Sponenberg, Carr, Simak and Schwink (1990), we know that its reasonable to consider the fewspot snowcap continuum in Diagram 2 to indicate the presence of two white pattern Appaloosa genes. A homozygous Appaloosa (LpLp) will produce offspring with Appaloosa colouring and/or characteristics 100% of the time, regardless of the breed it is crossed to (Diagram 3), because it gives one of its two Lp genes to every offspring. Note also from Diagram 2 that homozygosity in Appaloosas with less than 20% white patterning levels may be very difficult to verify visually. While there may be other physical signs that indicate homozygosity, these have not yet been confirmed in published studies. The findings of Sponenberg, et al, concerning the nature of the white Appaloosa gene are useful to both breeders and researchers. We now know that Lp is a dominant gene of some type. The way in which Lp behaves in homozygous Appaloosas appears to show incomplete dominance meaning two Lp
