Diamilina: How do you explain this case?

[Jorge]

This is a very curious case worth further examination and review.

The name of this broodmare is Diamilina (grey m 1998)

PEDIGREE: http://www.pedigreequery.com/diamilina
PROGENY: http://www.pedigreequery.com/progeny/diamilina

and she is the daughter of a grey sire out of a grey dam.
Ordinarily, these kind of produce tend to throw at the breeding shed
a fair number number of greys and solid color products,
unless they are genetically Grey Homozygous
(G/G), in which case all of their produce ought to be of grey color.

But the curiosity in this case is that she has consistently produced
8 grey foals from 8 different solid color sires, which may induce to
think that she is a grey homozygous (G/G) mare. Wrong! One of her
foals, the only one among her 9 foals is a “bay”.
All the rest are greys! Presuming all the crosses are correct, how do
you explain this anomaly?

Have you witnessed similar occurrences?

Please share your experience and what happened!

[Georgerz]

There two foals by Sinndar from 2009, one of which is listed as bay. But it may not be correct, as I don't think that the mare would have foaled twins that survived.

[Jorge]

Georgerz,

Thank you so much for the valuable watch!

Here is the correct fix:

The following horse named Obaghan (bay G 2009), by Sinndar out of Diamilina http://www.pedigreequery.com/obaghan
is an erroneous entry in several ways and should be eliminated right away from the Del Mar database.
Aside from the aforementioned inconsistencies, said horse does not appears as officially registered.
Isn't any wonder?


The only genuine Obaghan that is officially registered shows the following data:
Obaghan (Bay gelding 2009) by Azamour – Cloverte, by Green Desert.

Summing up, that means that all of Diamilina's produce are and ought to be grey.
Therefore, genetically speaking Diamilina is a Grey Homozygous (G/G) producer
thanks to the fact that both of her immediate parents are of grey color.

[MattieCat]

First off, many solid colored foals out of greys tend to be grey at birth, or shed out to be grey. If he is bay with no grey roaning at a few years old, he is probably not going to be grey. Some, though, do tend to grey as they age. Grey is a tough color, so it is best to test horses from grey parents for the grey gene, as it often expresses itself over time.
But, if she produced a bay, there is no way she is homozygous grey. You can't break the laws of science and genetics; it is already proven, which means people trying to prove it wrong couldn't. She is most likely heterozygous genetically, and a heterozygous grey will supposedly pass grey 50% of the time. Out of 9 foals, 8 of them are grey. At the moment she has an 88.8% chance at producing grey, just by easy calculation. That goes against the 50%, doesn't it? Weird, yes, but not completely uncalled for.
The best way to explain this is if I send you to random.org with specific directions. (optional, if you read further, I explain this clearly below the directions)
At the top right, you see a random number generator. Leave the minimum (1) and maximum (100) settings alone. Click *Generate* 10 times and record the 10 numbers on a piece of paper. Count how many numbers are 50 and below, then count how many numbers are above 50, including 100 if it shows up.

Lets say numbers 50 and below are not grey, and numbers above 50 are grey.
I got these numbers in this order:
18, 79, 80, 31, 76, 96, 18, 81, 76, 69

7 out of 10 numbers are above 50. So we can safely assume that, in this experiment, the random number generator (mare) tended to throw numbers (foals) over 50 (that are grey) than numbers below 50 (that aren't grey).
Simply, 7 out of 10 foals are grey.
That's how it works. It is probably confusing to most TB people since they don't really care about color, so they may think of 50% as a set percentage for every horse instead of a fluctuating percent that is different and constantly changing for every producing mare or stallion. You never really know a horse's set percent of color production until/unless the horse is sterile, no longer producing foals, or dead.
Example:
If I added a number (or foaled another foal and added its data) to the list above, it obviously would be 50 or below (not grey), or above 50 (grey). That would change the percentage of color production, b/c instead of 70% (7/10) of foals being grey, it would obviously be either 72.72% (8/11) or 63.63% (7/11) of foals being grey.
If a horse is no longer producing, sterile, or dead, your latest calculation on that horse's production would be your final and most accurate analysis.

[Jorge]

Mattie Cat,
Thank you very much for your thread. Very interesting! Can you abound a little
more on the first paragraph of your response.

[Pan Zareta]

Diamilina had a single male foal in 2009 named Diamapour. He was first recorded as bay, later corrected to gray. (Foal coats are notoriously deceptive.) He was never named Obaghan. That entry was apparently due to confusion between two colts foaled the same year in the Aga Khan's stud.

If Diamilina is heterozygous for grey the odds of her producing 8 consecutive grey foals are 1:256 (1/2 to the 8th power). She may very well be a homozygous grey but genotyping would be the only way to prove it.