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Does the genes define the expression of the tobiano pattern?

Hi! i'm new here! My mother tongue isn't english, sorry if i make mistakes ;)! I have this question for you: Does the genes define the expression of the tobiano pattern? If a horse is homozygous for the tobiano pattern and has the same expression of the pattern as seen in the middleleft picture. What if you breed this horse with a homozygous reccesive horse (a horse who hasn't got the gene for tobiano)... Does the foal got more chance to have the same expression of the tobiano pattern from the tobiano parent? So is there more chance that the foal will have the samen expression of tobiano as seen in the middleleft picture? [img]http://www.painthorse.com.au/register/regis_images/tobiano.gif[/img] An example: I have a Slipped tobiano buckskin foal born in 2011 (a solid paint bred). [img]http://94.100.124.5/1321000001-1321050000/1321013201-1321013300/1321013…] The dad of my foal is homozygous for tobiano (homozygous dominant). The mom of my foal is a QH (homozygous recessive). The half-brothers and sisters of my foal are regular paints (all the mothers are heterozygous for tobiano). Is it a coincidence that my foal is al slipped paint(he's the only one who has a QH mother)? Or is he a slipped paint just because his dad has this expresson of the tobiano gene: [img]http://www.stallionlocator.com/media/images/horse/nocona_2009_texel_wei…] I hope you guys understand my english and my question :)

rodeoratdogs Sat, 03/31/2012 - 11:33

It mignt have something to do with the Dam being solid, can you post a picture of her? Does she have any white? I think they might have mentioned that they were looking into that in the article I sent you. My slipped tobiano gelding's Dam was minimal white Homozygous just like your colts sire and his sire was Solid QH (not a stitch of white) so the same but in reverse.

You can see the parents here in his pedigree...
http://www.allbreedpedigree.com/i+cd+sp…

CMhorses Sat, 03/31/2012 - 12:13

Well it seems like the sire is a fairly minimal expression of tobiano and he also looks like he has sabino which could add to the white, and its possible the dam has a suppression gene too (opposed to not carrying any white genes). So with that combo the baby could have gotten a double dose of suppression genes, or just the tobiano from the sire which could be very minimal without the addition of another white pattern.

Daylene Alford Sat, 03/31/2012 - 22:50

Yes, it is possible that the dam and/or the sire carries a white suppressor that could have resulted in your foals low white expression. We know that low white can run in families but the exact mechanism is unknown. One of the current theories is that dark spots along the cornet band, such as the stallion exhibits, could be a sign of a white suppressor.

Slipped Buck Sun, 04/01/2012 - 05:03

What do they mean with a solid breedingstock? Is it a horse with white legs (like my foal) or a horse without any white?
[img]http://www.horseforum.com/userpix/4525_…]

And a 100% tobiano paint colored foal: do they mean foals who are registered as regular paint or foals like my foal?

"The majority of homozygous tobiano stallions standing today, sire 100% tobiano paint colored foals from the mares they breed. A few horses that are listed as homozygous, have sired the occasional solid breeding stock foal, but this is rare."
Source:http://www.stallingspainthorses.com/hom…

Monsterpony Sun, 04/01/2012 - 07:19

Tobiano always causes at least some white on the legs. The paint horse registry is not the most savvy on registering slipped tobianos so they will get registered as solid unless the leg white is high enough to qualify. It is really dumb. They register horses with paint patterns as "solid" all the time because they don't think it is white enough.

rodeoratdogs Sun, 04/01/2012 - 09:17

What MP said, but I emailed you the link for the coat color requirements did you get that SB? If not here is is again. So any white at least 2" above the center of the knee or the point of the hock, face white is also a qualifyer if it's enough(2" past the eye or the corner of the mouth), or any spot that at least 2". Anything that has less white would be considered "solid paint bred" even if it is genetically tested to have any white pattern ~x( .

http://www.apha.com/breed/colorreq.html

Slipped Buck Sun, 04/01/2012 - 10:04

In reply to by Daylene Alford

Ah ok :D
My colt has just a spot on his withers,but i don't think it big enough :)
There are people who use the term solid for a QH without white socks :-?

rodeoratdogs Sun, 04/01/2012 - 10:27

In reply to by Daylene Alford

[quote=Slipped Buck]Ah ok :D
My colt has just a spot on his withers,but i don't think it big enough :)
There are people who use the term solid for a QH without white socks :-?[/quote]

LOL! Oh boy don't get me started on the whole QH/Paint markings thing, I'll get off on a rant. You know that QH and Paints share all the same white mutations "except" Tobiano, but I would say that's debateable. Both in my gelding and your colt go back to a Tobiano with 2 QH parents....

Slipped Buck Sun, 04/01/2012 - 11:23

In reply to by Daylene Alford

I know, but if they mix the term solid (for a paint) and solid (for a quarter) no one gets the point (in a discussion on another forum) :? lol ^_^

rodeoratdogs Sun, 04/01/2012 - 11:42

What forum? :D Without looking at the discussion, this is where I think all the confusion comes from. Not long ago within the past couple of years AQHA got completely rid of there no white rule, so now QH's can also be registered Paint and vice versa, so when QH people refer to a QH being solid with no white they are meaning no white anywhere with a very good chance of not throwing a paint or any white because of haveing no white markings at all, and some QH breeder's prefer no white not even a star snip or a sock.

When APHA is refering to "solid" they are refering to their present rule.

Does that help?

Slipped Buck Sun, 04/01/2012 - 11:49

Yea, thanx!
I know the rule but there is alot confusion about it (and ofcourse when everything is translated into dutch :p). On the forum bokt.nl :)

rodeoratdogs Sun, 04/01/2012 - 11:56

In reply to by Daylene Alford

Ok good, yeah I would probably have a hay day(fun times) with that one if I could read it ;)

Slipped Buck Sun, 04/01/2012 - 19:05

I found an interesting article from the APHA about white patterns and coat colors.
http://www.apha.com/forms/PDFFiles/guid…

Some interesting quotes:
"A clue to identifying these “nonspotted tobianos” is that they tend to have a large amount of white on the lower legs but little white on the head. This combination is otherwise rare because it is usually the case that non-spotted horses with a great deal of white on the head have a large amount of white on the feet, and vice versa." - P 1
=> So a solid painthorse who looks like my horse is rare? He only has white legs, no facial white.

"Homozygous tobianos are beneficial to breeding programs due to their ability to produce tobiano offspring. Statistically, every foal produced from the mating should receive one copy of the dominant tobiano gene TO, thus creating a tobiano. Occasionally, a homozygous tobiano mating produces a solid-looking horse. This horse carries the tobiano gene but has only limited white markings. These horses are often referred to as minimal-white tobianos. For these horses, the tendency of the
tobiano to have a dark head and white legs holds true. The head may be completely dark or have very little white on it. However, the legs will show the specific characteristics." - P 5
=> But a solid painthorse with a homozygous tobiano parent who looks like my horse is common?

"Breeding a homozygous tobiano should produce all tobiano foals, with the exception of a rare minimal-white. A horse that produces five tobianos out of five solid mates is thought to have a 97 percent chance of being homozygous. Seven tobianos from seven solid partners increases the odds to 99 percent. Ten tobiano offspring from 10 solid mates increases the odds to 99.9 percent." - P 5
=> Is this just a big coincidence that my horse is a solid paint horse if his dad is a homozygous tobiano?

rodeoratdogs Sun, 04/01/2012 - 20:37

That is a neat "old" article, love the pics of Hot Scotch Man and Gambling Man, but this article is outdated I didn't see a date, but the Tobiano test has been around for quite awhile now and I noticed this in the Tobiano article...Currently, there is not a
laboratory test to identify the
tobiano gene....
Does anyone else here on the forum remember when the Tobiano test first became available?

So much changes so quickly with the availability of genetic testing...

I have books I bought from APHA in the 90's that has theory's about genetics that we now know are not right at all with the indroduction of genetic testing.

rabbitsfizz Fri, 04/20/2012 - 05:19

I wish the APHA would get the message that Tobianos do not actually have white on the head, that the Tobiano gene suppresses white forward of the shoulder. Things might be a lot simpler if the actual registering body took the time to learn the most simple basics of pattern formation.....