Pony of the Americas

Pre-implantation genetic diagnosis (PGD) is a procedure used to screen embryos recovered after uterine flush to determine sex and genetic traits through DNA testing prior to implantation in the uterus.

Glycogen branching enzyme deficiency (GBED) is a fatal genetic disorder that results from the inability to correctly store glycogen in several organs of the body.

Tobiano is a white spotting pattern characterized by white on the body that crosses the topline.

Splashed white is a variable white spotting pattern characterized by a broad blaze, extended white markings on the legs, variable white spotting on the belly, and often one or both blue eyes. Eight mutations in two different genes have been shown to cause the splashed white pattern.

Sabino is a white spotting pattern that is characterized by white markings on legs often accompanied by white ticking or roaning of the midsection and a blaze on the face.

Classic Roan is a white patterning coat color trait characterized by intermixed white and pigmented hairs in the body while the head, lower legs, mane, and tail remain colored.

The extension gene, or red factor, determines whether a horse will have a chestnut base coat color or a black or bay base coat color.

Dun is a coat color dilution characterized by lightening of the coat, with the head, lower legs, mane, and tail undiluted. Oftentimes, dun is also characterized by "primitive markings" such as a dark dorsal stripe, barring of the legs, shoulder stripes, and "cobwebbing" on the forehead.

Dominant white is a variable white spotting pattern caused by many different mutations in the KIT gene. The VGL tests for the five most common mutations known as W5, W10, W13, W20, and W22. Homozygosity for W5, W10, W13 or W22 is thought to be non-viable.