Common white facial markings in bay and chestnut Arabian horses and their hybrids.

The research studied the inheritance and genetic factors that influence the extent of white markings on the faces of Arabian horses, suggesting that horses with specific genotypes (E/e, e/e, E/E) show varying degrees of these markings.

Objective and Methodology

• The research aimed to understand the genetic factors influencing white facial and leg markings in Arabian horses, particularly in heterozygous (E/e) bay horses and homozygous (E/E) bay horses.
• The study used computerized data from the Arabian Horse Registry of America, which contained information on 35 sire families. A sire family includes a male parent (sire), his offspring (foals), and the female parents of the foals (dams).
• The researchers divided the facial region of the horses into five sections, assigning each a score from 0 to 5 based on the presence of white markings.

Assumption and Analysis

• The team assumed that if E/e and E/E horses had any differences in their white markings, this would reflect in a reduced mean score in the E/- group, as horses with these genotypes couldn’t be identified in the sire families.
• The facial scores of E/e and E/- horses were compared to determine if the assumption held true.

Findings and Conclusion

• The research findings revealed that Arabian horses with the E/e genotype had more extensive white markings than those with the E/- genotype.
• The data led researchers to conclude that the extent of white facial markings varies among horses with different genotypes (e/e, E/e, and E/E), with heterozygotes (E/e) showing an intermediate expression of the markings.

This research provides insights into the genetic factors influencing white facial markings in Arabian horses, contributing to a better understanding of the inheritance of physical traits in this species.