calling all Color experts, need your input

[Carolyn R]

My niece is home for the holidays and working on an equine genetics problem for college.

She is not a horse person, this is a science course for her, and of course the info presented is not done with a user friendly edge.

The professor is a horse person and I am telling my niece that there is more to the question than meets the eye.

I decoded the color info, but the equine color calculator will not give me a full range of results based on the info (too many modifiers I guess). The question...is there another coat calculator out there?

Anyone that is curious, here is the problem below......

The professer assigned her to finding out what the color genetic probability would be of a foal that has parents that are.....

a dam that has sngle copies of the following red, cream, dun, agouti, roan, and tobiano (which would make it a roan/dunskin/tobiano)Ee,Cc,Dd,Aa,Rr,Tt

the sire has single copies of the red, cream, dun, roan and agouti (making it a solid roan/dunskin)Ee,Cc,Dd,Rr,Aa

She must find out what color probabilities of the foal are, but.........

the teacher also said the dam is a tovero, hmmmmm, trick question? the dams color sequence does not include any overo, IDK if she wants them to understand that they must add an Oo to the sequence (and an OO dam would never exist since it would be a lethal white and it would never be possible for it to mature to breeding age), or the fact that the fictional owner was mistaken since the dam's given info does not include any lethal white info at all.

Told her she should ask, it may be that the teacher wants them to understand this and have that ah hah moment.

 

[targetsmom]

Do you think the roan might be a sabino roan and not just "roan"? And tovero could be frame or splash, or is the teacher including sabino roan as being "tovero"? See how confusing that word "tovero" is!!!

 

[Sue_C.]

Do you think the roan might be a sabino roan and not just "roan"? And tovero could be frame or splash, or is the teacher including sabino roan as being "tovero"? See how confusing that word "tovero" is!!!

Although the word tovero might be confusing, the genetic marker shown is for true roan...the sabino roaning would be totally different; and I would assume at this level, the instructor would know that.

HHMMMMmmmmm............

 

[Carolyn R]

I don't think it is meant to be read into more than what was given. The things that are throwing me off are her calling the fictional mare a tovero(the markers do show the tobiano gene as Tt just no overo at all). Being that it is an assignment that will be a test grade, I told her to either do two sets of answers one with the mare having Oo and one without( or she should email the teacher and ask). It seems to be a double edged sword, either go strictly by what was provided and assume the fictional owner is wrong about the horse including overo, or she wants the students to understand if "if I say overo, and expect you to include it, but a carrier can only be Oo, it is senseless to think the mare could ever be OO".

Regardless, the equine color calculator from animal genetics will not compute roan dunskin tobiano (with or without overo) X roan dunskin. It will not carry over the roan on the mare, I guess there are too many modifiers?

Anyone know of other color calculators?

 

[supaspot]

"the teacher also said the dam is a tovero, hmmmmm, trick question? the dams color sequence does not include any overo"

perhaps the overo is splashed white , there is no test for splash hence no markers

 

[jleonard]

Maybe the teacher simply meant to say tobiano and got confused? Have they discussed overo genes in class? I am learning this year that professors (some more than others) are far from fool proof! I have one that I've been fighting with trying to convince her that the second metacarpal (splint) is medial, not lateral. She refuses to believe it, even when I take in anatomy books and show her. Having teachers like that has made me rather cynical! If it was me I would email the professor and find out for sure.

 

[Carolyn R]

Maybe the teacher simply meant to say tobiano and got confused? Have they discussed overo genes in class? I am learning this year that professors (some more than others) are far from fool proof! I have one that I've been fighting with trying to convince her that the second metacarpal (splint) is medial, not lateral. She refuses to believe it, even when I take in anatomy books and show her. Having teachers like that has made me rather cynical! If it was me I would email the professor and find out for sure.

Yes, they have discussed the overo genes, so that is why I am wondering if she wants them to incorperate the overo into the scenario but wants them to comprhend the mare must be Oo not OO or if she just fouled up her termonology.

 

[rabbitsfizz]

This is why tovero is such a silly term, but she cannot get into that!

The foal will be Black, no white markings, because the foal is always the one colour you do not expect.

This is an unwritten, but certain, law of horse breeding, and the tutor should be well aware of it by now.......

 

[Little Hooves]

If the instructor posted a string of genetics, then I would stick to that. I doubt it's a trick question - don't know many professors that go that way anymore.If in doubt, though, of course ask for clarification. I would assume it was a mistake and the teacher is not asking for the student to put in more data that is not there. BESIDES, adding another gene to the mix will only cut probability numbers in half and add another "set" of color combinations. So if you want to shoot for extra credit, you can make your own clarification on the paper and add the extra information. That would probably impress the teacher more than anything. Usually they're not out to trick you, though.

And if you're looking for a calculator, this one is pretty darn good:

http://www.animalgenetics.us/CCalculator1.asp

Now, it gives you options for "Dunskin" and to add "Tobiano" but it doesn't give an option for "roan" HOWEVER, just check "gray" and substitute that for roan - wherever the result says gray, call it roan instead. Because they act pretty much the same. One copy is dominant and the horse with one copy will be roan or gray and looks the same as a horse with two copies.

To add Overo, just add another "set" of color combos to that with "Overo" at the end (and you can replace Tobiano with Tovero if you wish) and divide all probabilities by 2 to get your new results.

Hope that doesn't confuse you

I can see it all so clearly in my head.

 

[R3]

I'm not sure if they discussed it in their class, but there is debate about whether homozygous roan is a genetic possibility. Some say that a homozygous roan embryo (RR) is non-vialble and will not result in a pregnancy. If that is the case, then she would have to leave out any RR possiblity when calculating the probabilities and only count the Rr ones. Whether to include RR would depend on what the Professor has taught in the class.

Also, I don't think it was unintentional for the Professor to say the mare was 'tovero'. Tovero is a short-hand way to say a horse is a combinaton of tobiano and overo, but it does not specify which overo gene, or genes that the horse carries. There is a genetic test for the Frame overo gene (lethal white overo, LWO), but it was not listed for the mare. So, it is impossible to say whether the mare is an LWO carrier. Splash overo does not have a test, so could not have been listed, so you can't tell if she is Splash.

If the mare is LWO, she can only be heterozygous for the gene. If she is Splash, she could be homozygous or heterozygous.

I think she needs to clarify with the Professor, whether the mare is LWO overo, Splash overo, or both. And if she is Splash, whethe she is homozygous or heterozygous. Without that information, she can not give an accurate answer.

 

[ForeverFarma]

The mare is either tobiano or tovero- she can't be both. YOu can calculate using the simple Tt for tobiano, but in order to calculate for the tovero, you have to know what caused it, spalsh, sabino or frame.

This calcultor does have dunskin roan- scroll down to find it

http://www.horsetesting.com/CCalculator1.asp

 

[Little Hooves]

This calcultor does have dunskin roan- scroll down to find it

http://www.horsetesting.com/CCalculator1.asp

Looks like I didn't scroll down enough

I love this calculator!

 

[ForeverFarma]

Me too, though it was giving us some wonky results at first for our colt due this year till we fir=gured out we weren't putting the right info in!