Tobiano Patterns - Information and open discussion

[Silverine]

This topic is based on Totina's Leopard Pattern topic.

**Beware! This topic is under heavy construction. The first and second posts are liable to change often.**

This is a place for everyone who is interested in the tobiano pattern and how it works in the game, whether you are currently working with it or not.
The goal is to collect all our knowledge in one place and to discuss the results openly to help each other on the way to a full-white tobiano pattern.

Up-to-date
The text written in this post will be kept up-to-date with whatever new information is presented in this thread. This is going to make it much easier for anyone to jump right into the discussions and still have any clue of what we have figured out so far.
The second post in this thread will be kept updated with examples of gene expressions and other visual effects that we find interesting and want to figure out (or have figured out) the mechanics of.

What is allowed?
It will be allowed to link to studs and horses for sale, as long as they are relevant to any tobiano project.
Asking for a stud or sale with specific characteristics is also allowed if it will help someone to progress further with certain traits (like coat colour or amount of white in a certain area).

Please don't ask to buy your first tobiano horse here since this could add up to a number of "garbage posts" that don't add anything to the discussions/projects.

The information available
Original post on tobiano patterns: http://www.horseworldonline.net/forum/v ... =2&t=13432

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What is known:

* The To switch gene - is what causes any tobiano patterns to appear.
> Only 1 gene with 2 alleles, which means two variations of the To gene exists: "on" and "off".
-A horse may carry the switch for To without displaying any white markings if it does not carry any pattern genes.
-So far there has been no discernible difference between heterozygous tobiano and homozygous tobiano.
-AC Belgians, Forest Horses, North African Barbs, Shetlands, Tarpans, and Turkmenes can carry the To switch.

* Pattern genes - create the large white patterns on the horse.
> Unknown number of genes with an unknown number of alleles for each.
- All breeds in the Adoption Centre can carry one or more of the pattern genes even if they are not visible.

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Thoughts and progress:
This section is dedicated to collect our thoughts and observations about each subject connected to the leopard complex, whether it is spot size/density or patterns. Anything written under each category is open for further experimentation and discussion in order to be confirmed or debunked.

* The To switch gene - 1 gene/2 alleles __________________________________________________________
The functioning of the current To gene is fairly clear. However, this function could change with the introduction of other paint patterns. To is a mutation of the KIT gene, and if other white patterns are released on the KIT gene as well they may interact in interesting ways.


* Pattern genes _________________________________________________________________
Different AC breeds carry different pattern genes, coding for different areas of the body.

When crossed only within their own breeds, Belgians, Forest Horses, Tarpans, and Turkmenes only display small socks or stars with occasional stockings. They have not been known to throw any body white.

NABs have been found to carry genes mostly pertaining to the front half of the horses body from the hip forward to the nose, though they can occasionally offer coverage along the far hind leg, along the spine toward the tail head, or small socks on the near hind leg as well.

A typical NAB from the AC:



An AC NAB with face white:



An AC NAB with full far hind leg coverage:



Shetlands are more likely than NABs to carry white over the rear half of the body and are much less likely to carry face white. It is also common for Shetlands to combine tobiano expressions with the leopard complex.

(More pictures and details coming soon.)

[Silverine]

Reserving this spot for other information.

Non-visible To
It is possible for a horse to carry the To switch but still appear solid. If the To carrier has no white pattern genes it will not display any markings, though is still capable of throwing To foals.

For example: A To-marked foal from two solid parents.

Foal


Sire


Dam


Though the foal only had a tiny sock, that sock is still an expression of tobiano. As such, at least one of the parents must carry the To switch. As both parents are solid, this means that it is possible for To to exist with no visible expression, meaning the horse that carries it lacks any white patterning genes. When crossed with a horse that carries at least one copy of a white patterning gene there is the possibility of a white-marked foal.

The same stallion bred with a solid AC Turkmene produced the following foal, also with minimal tobiano markings:



Dam


When bred with a visible To mare, the same stallion again produced a foal with only minimal tobiano markings. This adds weight to the theory that the stallions carries the To switch, but no white patterning genes.



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Mixing To and Lp

It is possible for both Tobiano markings and the Leopard Complex to appear on the same horse. The markings do not interact in any discernible way other than that it appears that Tobiano white "covers up" white markings from the Leopard Complex. Admittedly it can be difficult to discern which white is "on top" of the other white, but Lp expression tends to have softened edges and other "color bleeds" that do not appear when covered by tobiano white.

Some AC Shetlands exhibit both Tobiano white and the Leopard Complex.

Examples:



This horse does not have a lot of interaction between the two white expressions, but the tobiano white on her far hind leg covers up a small bit of the leopard pattern on the same leg.



This stallion is an AC Shetland with a large amount of tobiano white covering sections of snowflakes form the Lp gene.

[BlackOak2]

Wow! wow, wow!
Well, thank you.

One small correction I think you missed.

What is allowed?
It will be allowed to link to studs and horses for sale, as long as they are relevant to any leopard project.

Second to last word, leopard.

I was going to add what very limited knowledge I had with AC stock, but you already hit on it!

Bookmarking topic...

[Silverine]

Wow! wow, wow!
Well, thank you.

I was going to add what very limited knowledge I had with AC stock, but you already hit on it!

Bookmarking topic...

Thanks for the catch! I'm working with some AC NABs right now, so hopefully I'll have some more info on them soon. I'm also going to add in my experiments with that Tarpan in the second post.

[BlackOak2]

Wow! wow, wow!
Well, thank you.

I was going to add what very limited knowledge I had with AC stock, but you already hit on it!

Bookmarking topic...

Thanks for the catch! I'm working with some AC NABs right now, so hopefully I'll have some more info on them soon. I'm also going to add in my experiments with that Tarpan in the second post.

Speaking of AC tarpans, I have a stud that I can't use. He must've been a glitch, because when I first picked him up, he had no markings at all.
He kept throwing socked foals however, so he's useless for me.
However, now he has a star under his forelock.

He doesn't have any foals. I would prefer it if he has a use, but right now he's eating, aging and he's become a lawn ornament in the pasture. In fact, he doesn't even have good evals for the quest horses I have unlocked.

So he's available for the taking for whoever wants, no price.

[Silverine]

Speaking of AC tarpans, I have a stud that I can't use. He must've been a glitch, because when I first picked him up, he had no markings at all.
He kept throwing socked foals however, so he's useless for me.
However, now he has a star under his forelock.

He doesn't have any foals. I would prefer it if he has a use, but right now he's eating, aging and he's become a lawn ornament in the pasture. In fact, he doesn't even have good evals for the quest horses I have unlocked.

So he's available for the taking for whoever wants, no price.

He might be interesting to cross with some non-visible AC horses (Arabs, etc). I sent an offer from my holding account.

[BlackOak2]

He might be interesting to cross with some non-visible AC horses (Arabs, etc). I sent an offer from my holding account.

That works great for both of us.
Occasionally, I'll get some odd one's like that from the tarpans I adopt. Next time I get a blank To carrier that throws patterns, I'll post it here again for these trials.

[Tjigra]

I want to bring an interesting pedigree to this project:
Kenco


That's not my work, I bought him as an adult stallion already. Judging by the extensive pedigree of tobianos, I believed he was a homozygous if there ever was one, however his last living foal (a red dun Baladi filly) is kinda proving me wrong. She is, however, by an Arabian mare, and Arabians are believed to not have Tobiano. I wonder now if the mare just switched the white off for the filly, but she probably still carries To?
Edited to add: I payed closer attention to the mare who produced the Baladi filly - she has two foals from tobiano stallions, both solid (the other sire is a definite heterozygous however). Her son from that other stallion has also produced two foals from patterned mares, where one is solid and the other has noticably less white than its dam. The mare is now in foal to another patterned stallion with a short but tobiano-only pedigree - I wonder how that foal turns out.

Another idea. A horse sim game I played a while ago used this for defining the shade of the base colour the foal inherits - like a row of 7 switches where either could be on or off. The more switches are on, the more intense, darker the colour of the coat. If all are off - you get a very light sandy bay for example, so light it could be mistaken for a buckskin. All switches on - a nearly black bay. I wonder if tobiano doesn't work alike, only the switches might work for a specific area each, and if they're all off, you get a tobiano with no white. I believe horses from the pre-tobiano era then should have all their switches set to off probably. That at least would explain why I could only get socked or stockinged foals from my pre-tobiano era mares I am yet to breed a more patterned horse (not that I've tried a lot).
Anyway, I just wanted to share this thought.

[Nazarach]

Reserving this spot for other information.

Non-visible To
It is possible for a horse to carry the To switch but still appear solid. If the To carrier has no white pattern genes it will not display any markings, though is still capable of throwing To foals.

For example: A To-marked foal from two solid parents.

Foal


Sire


Dam


Though the foal only had a tiny sock, that sock is still an expression of tobiano. As such, at least one of the parents must carry the To switch. As both parents are solid, this means that it is possible for To to exist with no visible expression, meaning the horse that carries it lacks any white patterning genes. When crossed with a horse that carries at least one copy of a white patterning gene there is the possibility of a white-marked foal.

The same stallion bred with a solid AC Turkmene produced the following foal, also with minimal tobiano markings:



Dam


When bred with a visible To mare, the same stallion again produced a foal with only minimal tobiano markings. This adds weight to the theory that the stallions carries the To switch, but no white patterning genes.

Just a little add i noticed kind of late, the dam in this case threw a To foal with a similiar pattern to the one above
Foal 2

in this case the sire was a To carrier but I guess he only gave the switch and the mare the pattern?

(Also, if it is of any help to this project, the To-foal with parents lacking the visible To can be sold as I don't really need it http://www.horseworldonline.net/horse/profile/1672487)

[Silverine]

Project is going slow because my internet is slow but I wanted to share my latest foals.

I finally got another foal from Roberto and a loud Tobiano mare. He once again threw a foal with minimal markings, adding more weight to the thought that he has To but no white genes.

Foal
- Little sock and even tinier star.

Dam



I've also been working with AC NABs, crossing them together to see what comes out. Here's the first pairing:

Sire


Dam


Foal

Interesting combo of parents. A bit of face white from dad, her shoulder marking is exactly the same as mom's except that it extends up her neck a bit further, like dad, and she got her dad's near hind stocking but not his far hind sock.