Homozygous Color Question

[mgtman]

I have been told that if both parents are homozygous, their foals will also be homozygous. Anyone know if this is true? Thanks, Bob T Bar T Miniature Horse Farm

 

[Mona]

: Yes, MOST DEFINATELY this IS true!

 

[Bess Kelly]

Well, they sorta "have to be"

: Now, depends on what they are homozygous for --- BUT, lets say both are homozygous for tobiano, then they can each ONLY pass that type gene to the foal, and when you have one tobi from each parent, that's what homozygous is.....2 tobi genes.

Of course, if one is homozygous for tobi and one for black, well you have more mathmatics, genetics and pure luck to consider :lol:

I'm not a "color expert" but, that's what I have gathered from it all.

 

[Loess Hills]

Bess is right. It takes one gene from each parent. Of course, what are they homozygous for? Tobiano, black, red, LWO??????

 

[Meavey]

LWO??????

That one wouldn´t be very alive...

:

 

[mgtman]

Well, they sorta "have to be"

: Now, depends on what they are homozygous for --- BUT, lets say both are homozygous for tobiano, then they can each ONLY pass that type gene to the foal, and when you have one tobi from each parent, that's what homozygous is.....2 tobi genes.

Of course, if one is homozygous for tobi and one for black, well you have more mathmatics, genetics and pure luck to consider :lol:

I'm not a "color expert" but, that's what I have gathered from it all.

: He is suppose to be homozygous for the pinto gene.

 

[rabbitsfizz]

The "Pinto Gene", per se, does not exist. Which pattern in particular??

A horse can be H/Z for Tobiano, Sabino and Splash.

Only Tobiano is testable.

:

 

[Southern_Heart]

Gosh Bob, I have one that I had tested. My, petite Mister Illusion is a black and white Pinto, His Dam, Royal Oaks Sprinkles of Sugar was a black and white Pinto and his Sire Grosshill EKS Painted Illusion was a gray and white Pinto and my Petite Mister Illusion test came back Heterozygous, not homozygous! I about fell out of my chair when the results came in. I thought for sure he would be. I was sure dumbfounded on it!

Joyce

 

[Songcatcher]

Gosh Bob, I have one that I had tested. My, petite Mister Illusion is a black and white Pinto, His Dam, Royal Oaks Sprinkles of Sugar was a black and white Pinto and his Sire Grosshill EKS Painted Illusion was a gray and white Pinto and my Petite Mister Illusion test came back Heterozygous, not homozygous! I about fell out of my chair when the results came in. I thought for sure he would be. I was sure dumbfounded on it!

Joyce

That should not be a big surprise. If you breed heterozygous Tobiano to heterozygous Tobiano, you only have a 25% chance of getting a homozygous Tobiano, 50% chance of heterozygous Tobiano, and 25% chance of solid.

 

[Charlotte]

Joyce, talk about falling out of your chair....when we bred homozygous (blood test) Cowboy to homozygous (blood test) Lace their first foal looked like THIS!

As soon as Frank had the sack pulled off of her I was saying "Turn her over! Turn her over!" I couldn't believe it! Just a couple of white feet was ALL!

We then had Cowboy, Lace and Paradigm (foal) DNA tested. All three are HOMOZYGOUS! LOL Doesn't that beat all???? LOL A few years later along comes the filly in my avatar from the same breeding. Now THAT'S what I was wanting!

Charlotte

 

[Shelley]

I have no idea, but we have been wondering how we go about having a horse tested. Our young stallion's sire and grandsire are both homozygous and so we are wondering if he might be, too.

Shelley

 

[rabbitsfizz]

An animal being H/Z for Tobiano only guarantees you a Tobiano- it does not guarantee you a horse that has a full coat pattern, only a coat pattern!!!

:

 

[Dona]

Joyce, talk about falling out of your chair....when we bred homozygous (blood test) Cowboy to homozygous (blood test) Lace their first foal looked like THIS!

As soon as Frank had the sack pulled off of her I was saying "Turn her over! Turn her over!" I couldn't believe it! Just a couple of white feet was ALL!

We then had Cowboy, Lace and Paradigm (foal) DNA tested. All three are HOMOZYGOUS! LOL Doesn't that beat all???? LOL A few years later along comes the filly in my avatar from the same breeding. Now THAT'S what I was wanting!

Charlotte

Many people are under the impression that having a horse who is homozygous for Tobiano will guarantee ALL their foals will be pintos. Not true. As Rabbit just said.....it will only guarantee that all their foals will "carry" the pinto gene. Some WILL be visual pintos....but some, (like Charlotte's lovely mare), will be "genetic" pintos...and look like solids with some white markings.

:

 

[Becky]

I have no idea, but we have been wondering how we go about having a horse tested.

I generally use the lab in FL, Avian Biotech. They are fast with the results and the tests are $25 per test. You can send in mane or tail hair.

I have a 2005 filly that I was just sure was homozygous. She has the characteristic 'ink spots'.

I had her tested to be sure and she came back heterozygous! I was so surprised! I even had her tested again at a different lab with the same results. Heterozygous for tobiano. So even characteristic ink spots and paw prints don't necessarily mean homozygous. This filly has had full siblings that were homozygous; she just didn't get two copies of tobiano herself!

 

[Shelley]

Thanks, Becky!

Shelley

 

[mgtman]

:aktion033: Thanks for all the great input. Guess I will spring the $25.00 and have the stallion tested. Thanks Becky for the link. Best wishes for a great foaling season for everyone!

: Bob

 

[Arne]

Hey, Just want to let you know of a page on our web-site we just set up. It helps predict color. We are still working on it but the basics are up and running. We are also adding Sabino testing to our list soon.

Thanks :bgrin

Arne

Animal Genetics Inc.

 

[Dona]

Hey, Just want to let you know of a page on our web-site we just set up. It helps predict color. We are still working on it but the basics are up and running. We are also adding Sabino testing to our list soon.

Thanks :bgrin

Arne

Animal Genetics Inc.

HEY....that is WAY cool! :aktion033: Can't wait until you can offer the Sabino testing too!

:

 

[rabbitsfizz]

I thought you could only test for one sort of Sabino??

 

[Arne]

I thought you could only test for one sort of Sabino??

We are working really hard on it and hope to have something soon.