homozygous tobiano-colour experts

[Genie]

Our colt is colour tested 100% for the tobiano gene, He has a lot of white with smokey black.

Would you expect more white on the resulting foals or is it a "crap shoot"

 

[rubyviewminis]

When you say 100% do you mean the test results showed homozygous? It is a crap shoot where color does not show, which is what white really is. But all foals from this horse will have the pinto tobiano pattern. Hope someone has more expertise to tell you.

 

[Blackwater Farm]

Does he have any blue in his eyes? From the facial markings it looks like there might be some sabino there too. Homozygosity just means that all foals will have a tobiano pattern, how much also would depend on the mare. Gotta remember that the stallion is only half of the equation and the mares genetics are just as important! He is very handsome!

 

[Kelsey]

Too many factors. You cannot predict how much white a foal will have. It will depend on the dam as well. The only thing you can predict is that it will be carrying one copy of tobiano from the sire.

 

[little lady]

No expert here...but in my experience with homozygus tobiano is that mother nature will express as much white or as little as she wants. Now the tobiano gene can be expressed in a slipped pattern where the horse does not appear tobiano but will gentically test tobiano. Clear as mud...huh.

 

[targetsmom]

Just wondering if you tested for lethal white (LWO)? With all that white on his face he must have some other pinto gene along with the tobiano. Since you plan to breed him, please test for LWO and if he is positive, then test your mares to avoid the chance of a lethal white foal. (Sorry if you already know this, but others might not).

He could also carry splash - was he checked for that? Not critical like LWO is, but additional pinto patterns will probably increase your chances of wild patterns. Now even if he is homozygous tor tobiano, that just means all the foals will inherit the tobiano GENE. But it could be expressed so minimally that the foal is considered solid - for example has one white foot.

 

[Carolyn R]

I agree that it is up to mother nature. The boy in my avatar is tobiano, heterozygous, but any form of tobiano will show on a horse that carries it. He only has white on his legs. Then there is a full size colt I recently brought home, his parents were both about 50/50 black and white and the sire was homozygous. The resulting colt, mostly

....so it really is up to mother nature. Quite awhile back there was a post with a homozygous tobiano who was very minimally expressed.

I agree that it is up to mother nature. The boy in my avatar is tobiano, heterozygous, but any form of tobiano will show on a horse that carries it. He only has white on his legs. Then there is a full size colt I recently brought home, his parents were both about 50/50 black and white and the sire was homozygous. The resulting colt, mostly white. He may be homozygous, but there really isn't any reason for me to test since he will be gelded once the weather cools off.

....so it really is up to mother nature. Quite awhile back there was a post with a homozygous tobiano who was very minimally expressed.

 

[Genie]

He does have partial blue eyes. I will test for LWO.

His dam had a lot of white and blue eyes, and the sire was sorrel and white homozygous tobiano very evenly marked.

 

[Genie]

Just an update regarding Genetics Testing in Talahasee. I called them to ask if I needed to gather hair samples again or could they test from what I sent in before. (LWO and Splash)

They said absolutely they could test using what I sent before and I would have the results Monday, by e-mail.

I thought that was wonderful service and might help someone who had sent samples for testing and needed more tests done.

Many thanks to all for the replies and your help and expertise.

 

[Lizzie]

Handsome boy Genie. I'll bet he also some some form of splash and some form of sabino, hiding in there. With homozygous Tobianos, nature can play tricks on us. I have seen many tobianos who appear to be solids. Maybe just have a white sock or two. They are just minimal tobis. I've also seen a few pure white Gypsy Horses, with just a touch of black on their ears, who were also tobis. They were just maximally expressed tobis. I've also seen completely white appearing horses, who were actually black, but were Sabino 1.

When we think of what makes a Tobiano, we must think of it this way. We have really, a (for example) solid black horse. Now we take a white sheet with a lot of holes in it and place over the horse. This sheet is the Tobiano. According to how big and how many holes we have in that white sheet, determines how much or little colour, the horse has. It is always a surprise.

Lizzie

 

[Genie]

Thanks Lizzie. I am really glad that Targetsmom gave me the "clue" to test for LWO.

That's why I come to the forum, for the wisdom of so many.

 

[Reble]

Hi Gene,

As you can see with our colt this year.

Picture of Sire: Positive for Homozygous tobiano tested negative for LWO

being he does have Rowdy in his bloodline.



Picture of his Dam:



Picture of colt this year., Only white on tail and legs.



Same Sire and Dam and they had this filly, more white with this one.

so you never know... for sure.. what mother nature has planned..

 

[Genie]

Thanks Mary. Did you test the filly and colt for Homozygous Tobiano?

 

[Reble]

Thanks Mary. Did you test the filly and colt for Homozygous Tobiano?

No I did not Genie.

Might do the colt thou? the filly was sold a year ago..

 

[MBhorses]

I have a mare who is homozygous for tobiano she was bred to my splashed black pinto stud they had a nice 2011 black pinto colt with blue eyes then this same mare and stud had 2012 a black min pinto filly with brown eyes nothing like her full brother. see them on my site

 

[Genie]

Update on the LWO tests suggested for this colt. He was negative for LWO. I am happy about that

 

[Joanne]

Genie I would test him for splashed white. There is more than homozygous tobiano pinto there.

 

[Genie]

I could do that too. I am no colour guru like a lot of you are. What would the knowledge of splashed white mean for me?

 

[Genie]

Joanne at Pacific Pintos is right!!!

Johnny carries one copy of the splashed white SW1 mutation.

Negative for Splashed white 2 and 3

negative for LWO.

I also tested his sister for LWO and she is heterozygous, carrying one copy of the LWO gene. ( Horse will usually exhibit the frame overo pattern.)

For breeding this mare I assume I will require the LWO test on the stud?

 

[rabbitsfizz]

Just because he tested H/Z for Tobiano does not, BTW, mean any of his white has come form Tobiano! Because he has so many other patterns in there (Splash and Sabino ) they could be supplying the white! Not that it makes much difference in the long run as it is, as has been said, a total crap shoot as to what pattern and how much white the foal exhibits.

He is a nice boy though, I hope you get at least a few "wild" foals!