Here’s a link to the 6 June 30th online edition:

And link to the study itself:

No paywalls on either site.


Already being discussed here :smiley:


Oops! Sorry. I skimmed through the topic titles and didn’t see anything mentioning the study, and wanted to share.

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If it’s any consolation, your thread title is way more useful! :rofl:


I’m not sure what thread to post this in, but I will post it here:

I read through the actual study and respectfully thought, “well duh.” I don’t think anyone believes inbreeding is without consequence. It’s very good to have some data to support that, though.

There is always this argument that inbreeding has increased in thoroughbreds. But has it truly? I say that because go back and look at some of the top sires of their day:

I mean, we’ve perpetuated this limited gene pool for centuries now, so surely that doesn’t help things. But thoroughbreds have never been the picture of genetic diversity.

Anyway, this article is exciting none the less. The fact that we can actually isolate some of the problematic genes in horses is fabulous news!


UK Gluck has just published a study which they call “the most comprehensive analysis of the genetics of the US Thoroughbred to date”. Their conclusion is that “diversity among Thoroughbreds falls within the range of other breeds of horses despite centuries of human intervention.”

UK Gluck Publishes Phase One of Genetic Diversity Study (

While I agree that the ability to isolate problematic genes is a good thing, my issue with the Soundness Study is their definition of unsoundness, which appears to be any TB that didn’t race.

I can quickly come up with lots of reasons why a registered TB might not race–none of them connected to unsoundness–and all of which have happened to us or people we know. (too slow, not interested, owner ran out of money, trainer retired, hurt in a paddock accident, EPM, van flipped over, not bred to race, stepped on a nail, bitten by a brown recluse spider, kicked by the stable pony etc etc) So it seems to me that the results from which the conclusions were drawn are somewhat skewed.


Good timing on that article. Interesting and not totally surprising. I grew up in the Arab breeding world and thoroughbred inbreeding has nothing on them!

I had the same problem with the set definition of unsoundness. Not racing is a poor indicator. But “unsoundness” is so hard to quantify in general because there are so many outside influences. Now that potential genes are identified, hopefully they can start assessing how they affect career outcomes.


One (very, very small) anecdote- one of my mares retired off the track due to a suspensory injury. Her half brother (same dam) also was retired due to a suspensory injury. They were bred by the same person, but each were owned and trained by different ones at the time of their injuries. So genetics possibly playing a role or predisposing them to injuries is certainly interesting.


Let me guess: Raise A Native/ Mr. Prospector/ Sadlers Wells? Pretty, athletic and tiny little fragile ankles.

She has Mr. P back in the 5th on her sire’s side, through Unbridled’s Song. No to Sadler’s Wells. pedigree:

Her half brother has Mr. P twice on his topside, in 3rd and 5th, but his tail male is through Storm Cat. His registered name is Alluring American. He was a recent “graduate” through the New Vocations program, but not sure who scooped him up.

I take it back, that’s a pedigree I wouldn’t have skipped over!

I will be very interested to learn in a few years what bloodlines this gene is associated with.


The Sadlers Wells in Europe must not have gotten this memo.

Really? I am from Europe and I would say that TB bloodlines in the US bred for early speed being very unsound is quite commonly discussed. As it is here in the US. It doesn’t mean they don’t sell as racehorses but TBs are rarely used anymore as crosses for sport and have fallen almost completely out of favor as riding horses.

Also you can just look at horses with many crosses back to RaN and see their very dainty legs and pasterns that are no wider than the cannons.

The article you posted is rather old news (2008). Ellen Parker made an entire career out of persecuting Raise A Native and his descendants, which doesn’t mean that her claims were correct, only that they were very forcefully stated.

To say that Eight Belles broke down because RAN appeared in her pedigree totally ignores that fact that–as the sire of Mr. Prospector–RAN appears in the pedigrees of literally tens of thousands of Thoroughbreds, only a minute fraction of which ever broke down. I wonder why no one ever asked Ellen Parker about that before accepting her “research” as gospel.


I am not sure I have the mental energy to reply to this as in depth as it deserves, but I am sure one of the many educated posters on COTH will see this and hopefully reply.

The discussion of soundness in TBs is often done by people with no real experience with racing. They often base their perception of soundness on TBs that are retiring from their first career – racing. Their pool of horses in which to assess soundness is already flawed as they are not dealing with unstarted TBs but TBs who have flunked out of racing or stepped down from racing and at 3 or 4 are already in their second career. Compare with warmboods, who at 3 or 4 aren’t even starting their first career yet.

The link you provided is an opinion article with zero factual basis. That person is one of those ‘vocal minorities’ that spent years trying to castigate a stallion that is now a dime a dozen in nearly every pedigree from Triple Crown winner to retired campaigner.

I’d be interested in the Verbands’ response to your take about no one in Europe breeding to TBs anymore. They are standing several racebred TBs for their WB mares. They might appreciate a gentle reminder from you.

Certainly what you say isn’t true in the US; some of our top athletes in the US are by or out of TBs. Some of our top event breeders in the US are breeding to TB mares and stallions.

If you are not familiar with racing, just know in the US that durability and soundness is a very studied topic and the Grayson JC ( puts forth tons of research every year about stallion durability, genetic diversity, breakdowns, etc.

This one might interest you. See how many times you can count RAN and Mr P in the top 10:

That list has been recently updated. For several years, Not For Love was #1 and then in top five once displaced. Looks like others have bumped him down but they are also by or out of Mr P horses.

If you want really interesting reading, check out the second graph (the green graph) that has average number of starts per starter. Go down the list and look at the pedigree of each stallion.


Here is Sadlers Wells, by the way (aged in this pic):

His son Galileo:

His grandson Treasure Beach:

Just for perspective. These three stallions have offspring that are being snapped off the track for eventing and event breeding. Because they can gallop and jump.


I’m pretty sure the only people who accept her research are horse lovers with Google. I have never seen it cited in a professional capacity.

Texarkana’s daily proselytizing on the topic:

To blame such a multifaceted problem on the genetics of a few horses seems very short-sighted. Even with identification of genes that potentially put a horse at risk, it isn’t a simple Mendelian inheritance of yes you will be unsound/ no you will not. Like cancer, Alzheimer’s, heart disease, etc., unsoundness results from both nature and nurture.

Going back to @Real_Rush’s example: conformational weakness are definitely inherited. The anecdote does not surprise me at all. But it doesn’t always work that way; if it was simply a matter of culling what we perceive as “unsound” horses from the breeding population, we would have solved this problem centuries ago.