K I T
KIT is a gene controlling certain patterns of white. Dominant white, rabicano, roan, sabino1, and tobiano are traced back to the KIT gene.
What we have to remember when trying to visually identify what white patterns a horse has is that all of the above are mutations of a single gene, and a gene consists of two alleles. Therefore a horse can be homozygous for any one of those or heterozygous for any two, no more.
White markings on the face and legs have been disputed. There are two extremes that either "no normal white markings come from pinto patterns" or "all normal white markings are just minimal pinto patterns". Both of these are widespread falsehoods! The fact is that sometimes these white markings are the result of pinto patterns, but a study on over 20,000 individual horses' DNA showed without a doubt that a single gene very close to the KIT marker controlled white markings on the face and legs of horses.
What we have to remember when trying to visually identify what white patterns a horse has is that all of the above are mutations of a single gene, and a gene consists of two alleles. Therefore a horse can be homozygous for any one of those or heterozygous for any two, no more.
White markings on the face and legs have been disputed. There are two extremes that either "no normal white markings come from pinto patterns" or "all normal white markings are just minimal pinto patterns". Both of these are widespread falsehoods! The fact is that sometimes these white markings are the result of pinto patterns, but a study on over 20,000 individual horses' DNA showed without a doubt that a single gene very close to the KIT marker controlled white markings on the face and legs of horses.