Ink Spots/ Paw Print Markings for visually identifying homozygous tobiano

These unique and distinctive markings are usually located in the 'white' hair areas on a tobiano and are small dabs of spots or color (1-3 inches) surrounded with prominent "blue zones" (white hairs on black pigmented skin that give the hair a blue appearance) surrounding the 'spot'. Usually there will be groups of prints that look like dog or cat tracks. These patterns tend to show up on homozygous individuals. Extreme examples above and below.

All equine parentage was originally verified through blood typing. Although researchers have never been able to identify a "color" gene, they were able to trace blood markers passed from the parent to the offspring for tobiano Paint horses. Studies were conducted on tobiano mares and stallions, and their resultant offspring. These studies led to the discovery of blood markers that are 'linked' to the tobiano gene. The prevalent theory is that the genes producing blood type are very close in location to the tobiano gene. Subsequently, when the gene for a blood type is passed along, the tobiano gene located next to it will be passed along to the foal, too. This process has been labeled 'linkage', and it makes the identification of tobiano status possible in foals from informative parents. Test breeding on solid mares is used to confirm the status of individuals thought to be homozygous, as it is possible for these genes to be 'unhooked' and not passed together. The horse above and below are both homozygous verified by blood typing. The horse above is a black obiano, and the horse below is a tri-color tobiano.
The tobiano below is not homozygous and will not produce color 100% of the time. Less value as a breeding sire, because there is no guarantee of tobiano, but may produce dun factor, and dilute colors which are popular, and that is the wonderful mystery and "hold your breath" anticipation of color breeding.