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Doc's initial test results from Stevenson University

rodeoratdogs March 20, 2011 March 20, 2011

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So as most of you probably know they used my 2008 APHA minimal tobiano gelding I CD SPOT "DOC" as an example in the recent article in the Paint horses journal on minimal/slipped tobiano's. In the article they asked for DNA samples for a study that Dr Susan Youngren is heading at Stevenson University on slipped tobianos, so I sent Docs DNA sample in for that as well, for the sample they also screened him for LWO & Sabino 1. Here is a copy of the test results, what is the significance of KM1? is KM1 always there in association with Tobiano?

horsegen Wed, 03/23/2011 - 13:45

The KM1 SNP is genetically associated with tobiano. Usually, horses who have the tobiano inversion also carry the KM1 SNP, but not always. So the SNP is often an indicator that a horse also has tobiano, but there is some degree of error. Most labs don't test for KM1, because they test for the inversion (which actually causes tobiano) and so there's no reason to test for KM1 too. But if this researcher is trying to look for differences between slipped tobianos and non-slipped tobianos, she's probably testing for KM1 just to see if she can detect any differences at that locus.

For you, it means nothing. Your horse has one copy of tobiano, and not surprisingly, one copy of KM1. He's what they would expect from a heterozygous tobiano.

rodeoratdogs Thu, 03/24/2011 - 21:19

Thankyou, yeah really nothing they tested for really means that much to me, he is a gelding after all. I just submitted his DNA for the research project they are doing because that is interesting to me , that's why I was wondering about the significance of the KM1. I found out about the research project from the recent article in the PHJ on slipped tobianos, they used a photo of him for the article.

rodeoratdogs Mon, 04/04/2011 - 22:17

Correct me if I am wrong, but it's when the tobiano gene is present but not fully expressed, when my gelding was first registered he did not have enough white to be registered tobiano, but I tested him and he does have one copy of the tobiano gene, so he is very minimal or slipped, besides his socks he only has that one very small spot on his neck. Some of the other horses they used as examples for the article were also positive for tobiano but had even less white like just a few short socks.

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RiddleMeThis Mon, 04/04/2011 - 22:31

[quote=colorfan]What is a slipped tobiano? Minimal expression?[/quote]
Yep. A slipped tobiano is one that is minimal, most likely registered solid, and may not look tobiano.

Monsterpony Mon, 04/04/2011 - 22:57

Yeah, your boy is pretty obvious tobiano to the trained eye. There are some that are definitely less obvious. Rabbit posted a pic of a mini once that had only a single black sock as a sign of tobi.

rodeoratdogs Mon, 04/04/2011 - 23:17

I remember that one a little back mini, I agree that Doc looks tobiano to the trained eye but alot of people would call him sabino.

colorfan Wed, 03/07/2012 - 07:39

Please tell me why when you see this horse and see his white chin you would think tobiano instead of sabino?

Inquiring minds want to learn....

rodeoratdogs Wed, 03/07/2012 - 09:17

[quote=colorfan]Please tell me why when you see this horse and see his white chin you would think tobiano instead of sabino?

Inquiring minds want to learn....[/quote]

The shape of his socks in the back out they travel up on the outside of his leg and also he has the ermine and distal spots on his socks which is common in minimal tobiano's. That being said my first clue was that his dam was homozygous minimal tobiano and his sire solid (not a stitch of white QH) so I knew it has to be in there. His face white would indicate that he does have another white pattern I'm thinking splash, he tested negative for Sabino 1.
He did test positive for one copy of the Tobiano gene n/Tb through Animal Genetics as well as through the study at Stevenson University.

I had found a link to the article on Slipped/Minimal Tobiano's in the FEB 2011 Paint Horse Journal he was featured in and posted on another thread here but for some reason it has been taken off line. I do have a copy of the article I can email you if you would like to read it just pm me and give me your email.