Multifactorial inheritance of white facial markings in the Arabian horse.

The research investigates the genetic inheritance of white facial markings in Arabian horses, concluding that about two-thirds of the variation in these markings can be attributed to genetics.

Research Hypothesis

The research was built on the hypothesis that:

• White facial markings in Arabian horses are down to multifactorial inheritance, meaning that multiple genes control their formation and distribution.
• Variations in these markings are influenced by alleles at different loci that act cumulatively.
• The amount of white on a horse’s face correlates with the number of genes involved.
• Interacting with non-genetic factors also affect the variations in these markings.

Research Methodology

This research used computerized data from the Arabian Horse Registry of America. The investigators established five facial regions and scored each horse based on white marking presence in these regions. They analyzed 22 sire families, each comprising a sire, his offspring, and the dams (mothers) of these offspring.

Results and Findings

Analysis of the research data, which includes regression analyses of sire-foal and dam-foal pairs, supported the proposed hypothesis. The research demonstrated that about two-thirds of the variation observed in white facial markings can be attributed to genetic differences among Arabian horses. This strongly implies a significant role of multifactorial inheritance in the occurrence and distribution of white facial markings within this breed.