Large heart"X Factor" Stallions

[Linda_d]

For me, this theory is like plenty others in racehorse breeding, looking for a magic formula that doesn't exist. The idea that the gene(s) for having a large heart that functions to enable it's owner to be an elite athlete are on one chromosome is utterly ludicrous. If it is so obvious, why aren't the people that "discovered" this theory having champions year upon year.

I agree -- it's too simplistic. There are too many genetic and environmental factors that make race horses great runners to just isolate one gene and claim that there's just one "magic" one. If that were the case, then "double copy" mares bred to sons of double-copy mares would always produce "double copy" fillies and single-copy colts that would have larger than normal hearts, and all would be great race horses.

The complex genetic codes that determine something as straight-forward as a horse's white markings -- or lack of same -- demonstrate just how complex genetic codes in diverse populations are. Getting a great horse involves much more than getting a horse with 2 white stockings.

[going4stamina]

Again, it is merely a part of the equation to have a genetic "help" in the larger than normal heart category...due to environmental, conformational, interest, attitude, and management issues, not all of those blessed with a larger than normal heart are going to be supreme athletes.

How many extremely bright students or human athletes don't apply themselves, get into trouble, or get injured?

[griff]

Good point going4stamina

Has anyone ever attended a Mensa meeting???

griff

[madelyn]

um, griff, I used to be a card carrying member of Mensa.. what's your point?

[griff]

Madalyn

I was responding to Going4stamina's comment about bright kids who did not take advantage of their potential and horses that did not take advantage of their large heart.

I must confess thst my exposure to Minsa was limited as I did not fit in and saw no reason to make an effort. Perhaps if I had tried other groups it would have been differient but I did not think it was worth the effort.

griff

[AscotStud]

Sort of off the path this tread was going but, Wild Wonder supposedly had a very large heart...and died of a heart attack at a young age (for a stallion).

[Patuxet]

I'm surprised that a "card carrying member of Mensa" could post something as unproveable as "Natalma who is probably responsible for the unsoundness in the Northern Dancer lines".

That sounds more like louis finochio or someone who's taken a correspondence course in genetics from Ellen Parker.

[madelyn]

Your RIGHT. I should have phrased that as "Natalma, who has been written about by others as the source of unsoundness in Northern Dancer lines."

We can blame the grammatical faux pas on the severe head trauma injury I got in 2003 that dropped my IQ 60 points, which I have been working very hard to recover from for the past six years. (I'm back up about 40 from that, but now age is creeping into the mix).

[jagger]

You're TOO much, Madelyn.

[Tonno100]

Well if you study the lines you will see where it falls true. It's common genetics. Australia has known about it years before the US and it took Secretariat for them to see the truth to it. Easy science.

For me, this theory is like plenty others in racehorse breeding, looking for a magic formula that doesn't exist. The idea that the gene(s) for having a large heart that functions to enable it's owner to be an elite athlete are on one chromosome is utterly ludicrous. If it is so obvious, why aren't the people that "discovered" this theory having champions year upon year.

It isn't common genetics, or easy science, to state as such shows a severe lack of understanding of genetics.

There are simple genetic conditions where a single gene change codes a defective protein, these are the kind that can be transmitted through one chromosome.

A change so drastic as a different sized heart would almost certainly cause an elevated foetal abortion rate, more heart problems etc, large hearts are, generally, not an advantage as it has a detrimental effect on blood pressure.

Like I said before, if that was the magic bullet, why isn't everyone doing it, or why aren't the people in the know dominating proceedings?

The example of Australia doesn't wash for a similar reason, if they've known for so long then why aren't they perennially dominating the world rankings??

[griff]

Are you suggesting that Secretariat did not have a large heart??

griff

[Tonno100]

Are you suggesting that Secretariat did not have a large heart??

griff

Absolutely not, what I'm suggesting is that it's not only unclear if that was responsible, per se, for his superb athletic ability, and that it is ludicrously unlikely that the genes for such a heart are on one chromosome.

[jagger]

Pass the popcorn

[LB]

You know, if you trot out the large heart theory at any of the big stud farms (with regard to their stallions) they will listen to you politely and then snicker behind your back after you leave.

This is not because they don't have a clear understanding of the genetics involved, but rather because they do.

[DDT]

Tonno 100

From the majority of your posts one could get the idea that you somehow feel that you know a little something about genetics in general and horses in particular. With that said, how can you be so sure that the gene or genes that determine heart size in the horse are not located on one chromosome. I am not saying that I agree with the theory, and I am not saying that all of Haun's assumptions are correct, but to say that it is "ludicrously unlikely that the genes for such a heart are on one chromosome" is not based on fact and is your assumption.

Make no mistake, I agree that in all probability the formation of a larger than normal heart requires more than one mutated gene, but I also feel that the genes or a particular gene carried on the X chromosome may be responsible for the formation of a larger than normal heart.

One thing I am sure of is that the genes carried on the X chromosome have a major impact on racing ability, if not, how is it that certain female families continue to produce superior runners generation after generation when in fact the only genes they continue to share undiluted are the genes carried on the X chromosome?

DDT