Genetics question for tobiano wild type allele

Hi everyone,
I've been through (to the best of my ability) the help boards and reading up on genetics. I see a TON has changed here since two years ago -- which is awesome! 

The genetics look far more realistic and this is amazing and I can't wait to get more familiar with EV again!

I have a question regarding the Tobiano. For a genotype as follows, what does the wild allele (+) mean, exactly, in terms of throwing offspring with the tobiano patterning? If I bred this horse with the below genotype, with another horse with T+, I'm not sure what I'd expect for the foal? 

The plus just means "none" essentially. Since the KIT gene has so many allele  types no single letter was suitable. so the + just means there is no other type of KIT displayed.

Thanks Sab! So essentially, does it mean if a T+ horse is bred with a horse with no allele for tobiano, that there is a 25% chance of the foal being tobiano? That's where I'm getting hung up. I'm trying to envision the Punnett square method here with alleles  and possible combinations for the foals. Perhaps I'm still not fully understanding the wild allele

It's not wild. Think of it as null instead. +=no expression. 

It will depend on what the other horse expresses in the KIT gene, but a T+ horse bred to a ++ horse has a 50% chance of being Tobanio. Because only one parent has an expressed KIT gene. 

Might be easier to visualize it as:
 
nn (none) [++]
nT (heterzygous tobi) [T+]
TT (homozygous tobi) [TT]

If you punnet square it, it would be like:

(nn x nT) 50% nT, 50% nn
(nn x TT) 100% nT
(nT x nT) 25% nn, 50% nT, 25% TT
(TT x nT) 50% nT , 50% TT

The breeding calculator also has a foal coat calculator you can use as well for hard % breakdowns c:

Last edited on 2021-03-21 at 08:53:09 by ᵍ ᵒ ᵃ ᵀ☀

Top and bottom percentages are wrong from Goat's post. Where one horse is has the same alelle and there is no incomplete dominance there is always a 50/50 split:

Thanks I'll fix that. Sleepy brain felt lije something was off but I couldn't discern which lol.

Thanks Sab and Goat!
For some reason, I was getting hung up on T+ being the same thing as heterozygous (Tt) for the gene, with one dominant and one recessive allele, but I see that isn't the case. : )
Goat, your explanation on how to handle the KIT gene in terms of the punnet square helps me! Thanks! 

Last edited on 2021-03-23 at 18:17:14 by Frosted Mint