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.
Roan is a white patterning coat color trait characterized by intermixed white and colored hairs in the body while the head, lower legs, mane, and tail remain colored.
Dominant white is a variable white spotting pattern caused by many different mutations in the KIT gene. The VGL tests for the four most common mutations known as W5, W10, W20, and W22. Homozygosity for W5, W10, or W22 is thought to be non-viable.