"Colors That Do Not Exist in Purebreds

Purebred Arabians never carry dilution genes. Therefore, purebreds cannot be colors such as dun, cremello, palomino or buckskin. However, there is pictorial evidence from pottery and tombs in Ancient Egypt suggesting that spotting patterns may have existed on ancestral Arabian-type horses in antiquity. Nonetheless, purebred Arabians today do not carry genes for pinto or Leopard complex ('Appaloosa') spotting patterns, except for sabino. ..."

Note:

"The leopard complex is a group of genetically-related coat patterns in horses. These patterns range from progressive increases in interspersed white hair similar to graying or roan to distinctive, Dalmatian-like leopard spots on a white coat. Secondary characteristics associated with the leopard complex include a white sclera around the eye, striped hooves and mottled skin. The leopard complex genes are also linked to abnormalities in the eyes and vision. These patterns are most closely identified with the Appaloosa horse breed, though its presence in breeds from Asia to western Europe has indicated that it is due to a very ancient mutation...." Leopard complex

"Spotting or excess white was believed by many breeders to be a mark of impurity until DNA testing for verification of parentage became standard. For a time, horses with belly spots and other white markings deemed excessive were discouraged from registration and excess white was sometimes penalized in the show ring.

To produce horses with some Arabian characteristics but coat colors not found in purebreds, they have to be crossbred with other breeds. Though the purebred Arabian produces a limited range of potential colors, they do not appear to carry any color-based lethal disorders such as the frame overo gene ('O') that can produce lethal white syndrome (LWS). Because purebred Arabians cannot produce LWS foals, Arabian mares were used as a non-affected population in some of the studies seeking the gene that caused the condition in other breeds. Nonetheless, partbred Arabian offspring can, in some cases, carry these genes if the non-Arabian parent was a carrier.

Genetic Disorders

There are six known genetic disorders in Arabian horses. Two are inevitably fatal, two are not inherently fatal but are disabling and usually result in euthanasia of the affected animal; the remaining conditions can usually be treated. Three are thought to be autosomal recessive conditions, which means that the flawed gene is not sex-linked and has to come from both parents for an affected foal to be born; the others currently lack sufficient research data to determine the precise mode of inheritance. Arabians are not the only breed of horse to have problems with inherited diseases; fatal or disabling genetic conditions also exist in many other breeds, including the American Quarter Horse, American Paint Horse, American Saddlebred, Appaloosa, Miniature horse, and Belgian.

For More Information:

Anglo-Arabian
Five Arabian Horse Female lines: Kuhaylan El Adjus, Siglavy, Habdan, Hamdani and Obajan
Arabian or Arab Horse Breed
Arabian Horse
Tobiano, Overo, Sabino, Tovero
Molecular Tests for Coat Colours in Horses
First posted: July 19, 2016
Last update: Jul 19, 2016