Secretariat sons with large hearts.

[Jorge]

How many immediate sons of Secretariat carried
large hearts like him, not because of him, of course,
but due to their broodmare sires? Any study?

[Jorge]

Just in case anyone wants to search on Secretariat's tail-male-lineage!
There is a previou topic titled:

Secretariat's tail-male-lineage alive!!

http://www.pedigreequery.com/forum/view ... ecretariat

[summerhorse]

i've never heard anyone bring it up before. INteresting question but I am guessing that if they carried the large heart gene they missed out on everything else that would make them stand out!!

The only stallion my feeble mind can come up with right now that carries the large heart gene is Atticus. I'm sure there are many more.

[Jorge]

This does not pretend to be scientific data to lean
on but who knows if some of the Secretariat sons who
clicked excellent racetrack times carried
big hearts. General Assembly my well be a good
example. I guess that close inbreeding to Secretariat
was something that wasn't an option.

[Patuxet]

Risen Star's heart size was discussed in the Sorry...another X factor question thread.

[Jorge]

Risen Star's heart size was discussed in the Sorry...another X factor question thread.

I guess this is the topic and these were the quotes:

http://www.pedigreequery.com/forum/view ... d24e3ed98f

xfactor fan expressed:

I asked to see at Risen Star one last time before he was buried. Maybe it was a strange or morbid request but I just wanted to have a look. His heart – and I couldn’t tell you what it weighed or how it compared in size to other equine hearts – was massive; the engine that powered Risen Star was as big as a soccer ball. Now, every time I watch a replay of the 1988 Belmont, in my mind I see this perfect engine driving him home.

Here's the quote from the very nice piece by Frances J. Karon.

Yes, an experienced observer, but admits that "I couldn’t tell you what it weighed or how it compared in size to other equine hearts"

I'm willing to believe that Risen Star had a large heart. But I'd be a lot happier if someone had weighed the heart , or the vet doing the necropsy had given an estimate, both of the size and the state of health.

My point is not if Risen Star had a large heart or not, but that this issue is only going to be solved by the application of good science.

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Then Patuxet expressed:

Like you "I'm willing to believe that Risen Star had a large heart."

Absent the science that proves otherwise, I just find it difficult to believe that his sire, Secretariat, would have had absolutely nothing to do with it.

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xfactor fan expressed:

One of the questions asked earlier in this thread is why the large heart hasn't been bred for.

The discussion about Risen Star is a perfect example of the problem. Large heart stallion sires large heart son. Must be related. Must come down from the top side of the pedigree.

Folks don't even want to consider it might come from the bottom side, or be related to mtDNA interacting with DNA on the chromosomes, or pseudo-sex linked. Or something that won't be discovered for another decade.

IF it is sex linked, then you can breed to a large heart stallion, and unless the females carry the large heart, you aren't going to get large heart colts. And if the large heart contributes to the racing success of the stallion, then the normal heart size colts will not approach the quality of the sire.

But no one in the breeding game is going to admit that their champion racehorse stud is going to be a dud. There is way to much money involved. I'm not suggesting there is a conspiracy--just that there are economic factors in play that don't want to look at the science.
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[summerhorse]

Yes I wasn't thinking, the large heart gene is carried on the X chromosome which means it is passed from sire to daughter only. If Risen Star had a large heart then he would have gotten it from his dam (who I don't even recall offhand!) This is part of what made Secretariat a tremendous broodmare sire.

[Jorge]

Theoretically, Secretariat's sons, out of mares whith strong Princequillo
influence (let's say, High Echelon) or War Admiral my be good candidates
for a close look.

[Patuxet]

When are people going to stop babbling about the myth of a large heart being carried on the X chromosome? The notion has been totally debunked.

As Byron Rogers wrote over two years ago on another forum:

"At the recent Pedigree & Genetics symposium four world respected equine geneticists - Dr Jamie Macleod, Dr Emmeline Hill, Dr Steve Tammariello and Dr Matthew Binns, all confirmed that the myth of the x-factor was exactly that....a myth. Three of the four geneticits mentioned above were part of the Horse Genome project that sequenced the horse's genome and Dr Binns co-wrote the original horse genome map."

"There is no evidence whatsoever in their studies that the inheritance of such genes follows the mystical pattern as described in Marianna Haun's books. It is romantic to think that the great mare Pocahontas has in some way weaved her magic through the maze of inheritance and recombination of genes, but it just doesn't work that way. There is no fabled "x-factor" at work."

To that Byron added the following, which caused my suspicion (quoted above) as to the source of Risen Star's heart:

"Scientists who study heart size are now finding that the sire has just as much of a role in determining heart size of the resultant foal as the mare. As an example, in talking to quite a few of the companies that measure hearts they have mentioned independently that the stallion Tapit is almost homozygous for heart morphology with his colts and fillies getting a similar heart shape to his own."

[Jorge]

As Byron Rogers wrote over two years ago on another forum:

"Scientists who study heart size are now finding that the sire has just as much of a role in determining heart size of the resultant foal as the mare. As an example, in talking to quite a few of the companies that measure hearts they have mentioned independently that the stallion Tapit is almost homozygous for heart morphology with his colts and fillies getting a similar heart shape to his own."

Interesting Would really like to read the complete text.

[Pan Zareta]

As Byron Rogers wrote over two years ago on another forum:

"Scientists who study heart size are now finding that the sire has just as much of a role in determining heart size of the resultant foal as the mare. As an example, in talking to quite a few of the companies that measure hearts they have mentioned independently that the stallion Tapit is almost homozygous for heart morphology with his colts and fillies getting a similar heart shape to his own."

Interesting Would really like to read the complete text.

Click here. Scroll to the last post on the page. Patuxet's correct. Genomic analyses have yielded no evidence whatsoever to substantiate the hypothesis that heart size is controlled by the equine X chromosome. Exclusively Equine sells DVDs of the '10 and '11 Pedigree & Genetics symposia. Iirc, there was more discussion of this subj. in '10.