Coloured Tobiano - Breeding and Genetics Information from Angrove Stud

Coloured Tobiano

In horse genetics, a Tobiano is a type of coloured horse. A coloured horse is given this type when there is a greater or equal amount of white on black or brown.

In horse genetics, Tobiano and Sabino are known as "dominant" genes, meaning they have two different allele - see our page on homozygous horses for more information.

A Tobiano coloured has clean-cut, rounded coloured markings, with white legs and white across the withers. A Tobiano head will typically be dark coloured and may have white facial markings. A Tobiano appears to have less black or brown than white, but in fact a 1/1 ratio is preferential – there should equal amounts of colour and white.

The Tobiano is by far the most prevalent type of coloured horse. Our coloured stallion Ricco is Tobiano. Our colt, Angrove Spotted Dick, is homozygous for Tobiano.

This is what the Wikipedia page on Tobiano states are general Tobiano traits:

• White legs from the hocks and knees down
• White crossing the back between the withers and the dock of the tail
• White is arranged in a vertical pattern
• Facial markings like that of a solid-coloured horse. i.e. star, snip, strip, or blaze
• White patches which are usually rounded or oval in shape, rather than jagged
• Dark colour extending down the neck, giving the appearance of a shield
• Can have ink spots this does not mean they are Homoygous it means they have spots as basicly the tobiano is part of the spotting gene complex found on Kitt.

Read more about the other coloured horse types: Overo and Sabino.

Coat colour explained in pictures.

 

    

Black                             Chesnut                      

The layperson guide to breeding a coloured horse,

all horses start with either Black or Red or a combination of the two one of each

  

The Agouti Gene or bay & the Grey gene

next come the modifying genes and one of them is  Grey and Agouti or bay which inhibits the placement of the black gene, ie it tell's the black gene were to go legs, main, tail ,points of ears, a chestnut horse can carry agouti and its hidden and is only seen when mated to a black carrier which it will then modify.

The grey gene can work on any colour base coat and can modify any dilution genes as well

Black horses do not carry agouti otherwise there black would be like a bay.

a chestnut horse is Homozygous for Chesnut but can carry other modifying genes. Agouti/ spotting genes/ and diliution genes

 

bay diluted once by the cream gene & Palomino is again diluted by the cream but this time acting upon the Chestnut.

The diliution gene cream acts on bay to make the coat a golden colour when it is diluted by one single gene.

The Spotting genes are again modifying genes that stop the pigment on the skin of either a back or red based coat.

     

Chestnut & white tobiano Black & White Tobiano & Bay & white Tobiano

this is how the dilution genes look in Tobiano along with the grey gene which will fade should the horse inherit grey from its sire or dam

     

So how do you try to breed for Homozygous you need to start with two tobianos, which can be Heterozygous 1 copy of tobiano or Homozygous 2 copies of Tobiano.