Different dominant white mutations occur in different breeds and lines

We have already seen that dominant white mutations have originated independently on several occasions, so that different mutations occur in different breeds, and even in different lines of the Thoroughbred. So far (July 2009) eleven separate Dominant White mutations have been characterised and documented in eight horse breeds.

Some breeders have indicated surprise, or even disbelief, that several different mutations in the same gene should be involved in causing a white phenotype. However this situation isn't an unusual one. In mice there are more than 90 known mutations of KIT, and various KIT mutations are known in other animals. Among other things KIT mutations in other animals cause white coat color and spotting patterns, as discussed on the main dominant white page. Some of them are also known to be lethal when homozygous.

Anyone wanting a laymans summary of the basic details of the different mutations should start with Nancy Castle's article, Equine KIT Gene Mutations. ~Dominant White & Sabino ~ at

http://www.duncentralstation.com/PDF/KITGeneMutations-Castle.pdf