Heterozgous tobiano
   

       The Horse Forum > Horse Breeds, Breeding, and Genetics > Horse Colors and Genetics

Heterozgous tobiano

This is a discussion on Heterozgous tobiano within the Horse Colors and Genetics forums, part of the Horse Breeds, Breeding, and Genetics category
  • Minamally expressed tobiano
  • Minimal tobiano

 
LinkBack Thread Tools
    08-14-2012, 11:37 AM
  #1
Weanling
Heterozgous tobiano

Hi,
Probably a pretfy simple to answer question for you guys - I came across a horse for sale ad the other day that had the picture of a solid bay horse, and stated that the mare had been tested heterozygous tobiano. I always thought that tobiano was expressed even if it's heterozygous, hence a homkzygous tobiano throws only tobiano foals... is that not true?
Posted via Mobile Device
     
Sponsored Links
Advertisement
 
    08-14-2012, 12:04 PM
  #2
Trained
Horses with white patterns are not always obvious; however, tobiano almost always expresses itself. There was a mare posted not long ago that was of the most minimally marked tobianos I've seen.

Could you link the ad?

And yes, a homozygous tobiano will always pass on the tobiano gene whereas heterozygous will pass it on 50-50.
     
    08-14-2012, 02:23 PM
  #3
Green Broke
Agreed. If it is homozygous, the gene will pass on, but if it is heterozygous it is not a guarentee.
     
    08-15-2012, 07:12 AM
  #4
Weanling
Here's the link:

Broke to ride - APHA mare in foal to CBHI Stallion - Alberta Livestock For Sale - Kijiji Alberta

So would the face and leg markings be enough to be considered minimal expression of the tobiano?

On another note, that means solid, APHA registered Paints mostly have one or more overo genes, right? (since tobiano would be expressed most of the time)
Posted via Mobile Device
     
    08-15-2012, 11:43 AM
  #5
Green Broke
Quote:
Originally Posted by Regula    
Here's the link:

Broke to ride - APHA mare in foal to CBHI Stallion - Alberta Livestock For Sale - Kijiji Alberta

So would the face and leg markings be enough to be considered minimal expression of the tobiano?

On another note, that means solid, APHA registered Paints mostly have one or more overo genes, right? (since tobiano would be expressed most of the time)
Posted via Mobile Device
She doesn't look it to me, and I would never peg her for tobiano if it weren't for the DNA testing; most of the time minimal tobianos at least have a bit of white in their tails. But of course, genetics don't always follow the "rules"

Many of the SPB registered horses do carry some type of overo (which hides more frequently), but some of them also carry no pinto genes at all and are the product of heterozygous parents who didn't pass along the gene.
     
    08-15-2012, 02:43 PM
  #6
Trained
Possibly she might. I'd ask to see the copy of the test results if I were really interested. However, she's most likely got frame and splash going on too. Tobiano doesn't put white on the face like that.

And yes, many horses registered SBP actually do have a white pattern. Mine has frame and is registered BS. Some are actually just solid though. For the APHA, phenotype is far more important that genotype.
     
    08-16-2012, 01:11 AM
  #7
Green Broke
Homozygous tobiano (tested)



Heterozygous tobiano (tested)



Another tested Homozygous tobiano mare



Tobiano can be very minimal and yet still be there. I have yet to see a horse test positive for tobiano and have no white on them at all, usually they will have at least a heel spot on a back foot from what I have seen/heard about. However, with the attitude that "normal" leg and face white isn't related to white marking genes, there may be "solid" horses that have tobiano and just aren't tested for it as the owners don't realise that it could still be there.
     
    08-16-2012, 01:29 AM
  #8
Showing
Yep, that's the funny thing about white pattern genes. Just because they carry them doesn't guarantee that they will express them.
     

Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
Tobiano with....? Ladybug2001 Horse Colors and Genetics 1 08-10-2012 09:55 PM
Tobiano and.... What? jingojewel Horse Colors and Genetics 21 06-16-2012 09:30 PM
Tobiano,Tovero-tobiano/sabino? ladytaurean515 Horse Colors and Genetics 23 04-03-2012 10:09 PM
Tobiano and what else? SunnyDraco Horse Colors and Genetics 18 03-16-2012 03:41 AM
New Tobiano! irisheyes12 Horse Artwork 9 07-02-2008 02:37 PM



All times are GMT -4. The time now is 06:45 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0