What is the difference between a white horse and gray?

The main difference between a white horse and a gray horse lies in their genetic makeup. A white horse is born with a white coat due to a specific genetic mutation that suppresses all pigment production, resulting in a lack of color in the hair, skin, and eyes. On the other hand, a gray horse is typically born with a dark coat that gradually lightens over time as they age, due to a progressive graying gene that causes the hair to lose pigment.