What will happen if I breed a grey horse to a homozygous Tobiano Pinto?
If you breed a grey mare to a homozygous tobiano pinto stallion, you will get a tobiano pinto foal. Whether or not the colored parts of the pinto coat eventually gray out over time, will depend upon whether or not the foal inherited the gray modifier gene from his parents. It only takes 1 copy of 2 possible copies received from each parent to turn the colored portion of the coat to gray over time. There is currently a DNA test to test for the grey modifier gene, it is offered here http://www.animalgenetics.us/Gray.htm . You know a horse has at least 1 grey modifier if the coat color is grey. If a grey horse has 1 grey parent and 1 non grey parent, than you know that the gray horse has only 1 copy of the grey modifier gene. Just because a grey horse has 2 grey parents does not mean that the grey horse has 2 copies of the grey modifier gene, the only way to know for sure is to DNA test for homozgyous gray. The picture shown to the left is of a grey and white tobiano pinto arabian Yearlin
