speedy gene(s)

  • Mavourneen
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speedy gene(s)

13 years 11 months ago
#144845
Got this off the New Scientist website: a decent science publication but (warning!) not long-term, articles are meant for consumption and come out every day. How useful this genetic rsearch may be at ground level is a subject for debate ... still, it's interesting.

Speedy genes: Making horses for courses

* 30 June 2011 by Anthony King

Horse breeders have always put their faith in bloodlines when it comes to finding a winner – now they're putting science into their stud books

See gallery: "The not-so-natural history of horse evolution"

AND they're off! It's the 2.35 at the Curragh, county Kildare, on the first day of Ireland's flat racing season. In the nick of time I manage to place a €5 bet on Whip Rule, a 2-year-old colt. His odds don't bode well - 10/1 in a six-horse contest - but I still think I'm on to a winner. That's not because I've had a hot tip from a stable boy, but because I'm confident my horse is made of the right stuff for this race.

Genes are everything for thoroughbred racehorses. Yet although horse racing has grown into an international multibillion dollar industry, racehorse breeding still relies on the same tools as it has for the past 300 years: pedigree charts, and trial and error. Now, however, the horse industry may be placed on a more scientific footing. In the past few years there has been an explosion of interest in horse genetics, and last year a test was unveiled for a "speed gene".

This research could help us humans too, by shedding light on people's exercise abilities and helping to combat the effects of today's sedentary lifestyle. Over the years, horses have been bred for exercise ability, says geneticist Emmeline Hill, who developed the speed gene test. "We can learn something from the horse as a model, in terms of the genes that are contributing to a healthy metabolism."

Wild horses were plains animals adapted for flight. Since their domestication about 6000 years ago, animals have been selected for speed and strength, a process that has been taken to extremes with thoroughbreds. All half a million or so registered thoroughbreds in the world are descended from three Middle Eastern stallions and about 70 brood mares from Britain and Ireland in the 16th and 17th centuries.

More than three centuries of breeding have turned today's thoroughbreds into running machines. They have huge hearts and lungs, and their muscle accounts for a phenomenal 55 per cent of their body weight, compared with 30 to 40 per cent for most mammals.

The huge sums of money tied up in racing and in other horsey pursuits such as show jumping and rodeo have led to serious investment in the study of equine genetics. In 2003 the first horse was cloned, and while clones cannot be registered as thoroughbred racehorses they can take part in other equestrian sports.

Following the sequencing of the horse genome in 2006, a few firms have started offering tests to predict racing ability based on patterns of variation among various regions of DNA. How effective these predictions are remains to be seen, but last year the horse world sat up and paid attention with the publication of Hill's test (PLoS One, vol 5, e8645) - the first to be based on a single gene with known relevance to racing ability.

Hill's group, based at University College Dublin, Ireland, looked at the myostatin gene, which normally acts as a brake on muscle development. In animals as diverse as mice and racing whippets, mutations have been found that stop the gene from working, endowing the animals with bulging muscles.

Myostatin appears to affect muscle mass in people too. In 2004, an extraordinarily muscular German child was found to have a mutation in both copies of his myostatin gene (The New England Journal of Medicine, vol 350, p 2682). At just 4 years old, he could hold 3-kilogram dumb-bells with his arms extended. His mother, who had just one copy of the mutated gene, was a professional sprinter.
In the blood

Hill herself is not without a pedigree, coming from a family that has bred and raced horses for generations. Her grandmother owned the Irish champion Dawn Run, a relative of the even more famous Seabiscuit, and rode as a jockey at the age of 62.

But Hill prefers studying horses to racing them. Her team focused on a point on the myostatin gene that can carry either of two bases: cytosine (C) or thymine (T). As horses, like us, have two copies of most genes, there are three possible combinations for their myostatin genes: C/C, C/T or T/T. Hill's group tested 179 elite racehorses and found that C/C horses are speedy types that do best at short races of 8 furlongs (1.6 kilometres) or less, while T/T horses have more staying power and do best at longer races of up to 20 furlongs. C/T types come somewhere in the middle (see chart).

"Once you know the type of your horse, you can train it for what it is genetically made to do," says Hill, who has started up a campus company, Equinome, to market the test. "A marathon runner is never going to beat Usain Bolt over 100 metres, regardless of training."

Searching through the thoroughbred genome for other variants linked to athleticism, Hill has found that genes for insulin signalling, fat metabolism and muscle strength have been strongly selected for in recent history (PloS One, vol 4, e5767). Understanding such genes could help lead to the development of new drugs for obesity and diabetes, she suggests.

So what does the horse world make of this new approach? At horse sales, Hill hears buyers wondering if a horse is C/C or T/T, and the jockeys and lads in the training yards are talking horse genotypes. In the past, breeders used pedigrees as a proxy for genes, but Hill's test marks a shift, says Ernest Bailey, a geneticist at the University of Kentucky who was the coordinator the horse genome sequencing project. "As breeders use the actual genes in their evaluations, they are going to be more successful in producing the horses they want."

But genes are not destiny. "We will still need to run the races to see which of the superior horses is best," Bailey says. "The answer is not going to be in a test tube." He also points out that there is probably no such thing as a single speed gene - there must be many genes that affect a horse's performance. "Success is achieved in many ways," he says. Horses "win races because of the diversity afforded by genetics, management and training".

Maybe so, but back at the racetrack the test is all I've got to go on. Hill naturally keeps the results confidential, but I've heard that trainer Jim Bolger has been using the test in his stable. The 2.35 race is only 5 furlongs, so I'm convinced Whip Rule is C/C - a born sprinter.

The race is over in a flash. Whip Rule is one of two horses that are neck and neck as they charge the finish line. Sadly my horse is just beaten by a "short-head". There are raucous celebrations in the stands from the winning ticket holders.

But then a steward's inquiry is announced. Ten minutes later the leading horse is judged to have drifted in front of Whip Rule and my horse becomes the winner. Oh happy day!

From then on I make further bets on Bolger's horses: I win some and lose more, but still end the day €30 up. Whip Rule has shown he has what it takes. After all, it's in his genes. Probably.

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  • Dave Scott
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Re: Re: speedy gene(s)

13 years 11 months ago
#144847
Cheers MAV (tu)

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  • marvs
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Re: Re: speedy gene(s)

13 years 11 months ago
#144914
Good
stuff Mav. I wonder what a test like that would cost us here in SA.

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  • oscar
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Re: Re: speedy gene(s)

13 years 11 months ago
#145090
Hey Mav nice article very interesting much like they isolating all the human problamatic genes , way to go avoid the disease much easier than treating it..Im looking for a fast filly with those speed genes ..or sorry jeans..if you know of any for lease??

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  • Don
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Re: Re: speedy gene(s)

13 years 11 months ago
#145134
producing the horses they want...horses with a quick roi....who mature early rather than late....will this not cause the middle and stouts to be more unfavoured at sales and ultimately we will end up with a breed pool or market demand for quarter horses only?

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  • Mavourneen
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Re: Re: speedy gene(s)

13 years 11 months ago
#145177
Don, I'm a little sceptical if this "gene" really is as important as all that. There are lots of genes for lots of characteristics affecting running ability, and they can't all be checked. I posted this more for debate than as the last word on the subject. What do you think?

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  • zsuzsanna04
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Re: Re: speedy gene(s)

13 years 11 months ago
#145186
I think if we wanted things based on logic and science, we wouldn't be in horse racing !

I'm sure science is moving along fairly rapidly, but despite our selective breeding for the past few hundred years, Thoroughbreds do not mature any faster or slower than any other breed.

Dr Deb Bennett has published quite a bit on the subject, her most well-known article being 'The Ranger Piece'.

www.equinestudies.org/ranger_2008/ranger_piece_2008_pdf1.pdf

You can also reference schedules of growth plate closures in Adams Lameness in Horses and Clinical Radiology in the Horse.

As to a speed gene, well, IMHO equine medical knowledge is still relatively (I do say relatively) primitive. If we can't find answers to EIPH or AHS, well, I'm not sure we're up to breeding a super horse just yet...

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  • oscar
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Re: Re: speedy gene(s)

13 years 11 months ago
#145222
I must add..this ridiculous theory that you will breed out bleeders by not allowing the use of furosemide is a joke...I assume they using Darwin's Theory of Evolution..

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  • zsuzsanna04
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Re: Re: speedy gene(s)

13 years 11 months ago
#145226
Oscar, it comes down to whether you consider bleeding to be an unsoundness. I happen to think it is. And I think it is irresponsible to perpetuate unsoundness.

The big issue is that we don't use natural selection when breeding Thoroughbreds,we use stats. And in general we are breeding for the sales ring or the race track. Which means that we're selecting for commercial bloodlines and speed.

Now,imagine if those fashionable, speedy bloodlines carried a genetic predisposition for bleeding, but due to Furosemide use,it never showed while the stallion was competing ?

Imagine if, for example,it turned found out that Northern Dancer was a bleeder? Pretty scary as you'd be hard pushed to find a horse in South Africa that doesn't carry that bloodline.

There's an old expression that knowledge is power. We try to avoid breeding horses with skew legs or other conformational defects for good reason. Because we know that bad conformation compromises a horse's ability to move economically, correctly & safely.

However legs & external conformation is something that anyone with a bit of knowledge & experience can see. With an issue such as bleeding you're relying on the integrity of the stallion owner & I'm afraid I just don't trust people to be that honest.

The use of furosemide effectively masks bleeders. And if no-one knows/realises a horse is a bleeder (and how do you know unless it actually bleeds), then how do you avoid it ending up in the breeding barn? If a horse is a multiple Group winner, but has been treated / managed for bleeding, how many stallion owners are going to stand hand on heart & say, well, yes he's a brilliant racehorse,but you probably shouldn't breed with him because he bleeds.

So you joke about Darwin's theory, but that is effectively what we're talking about. Unless we cut out the use of furosemide, we will never eliminate those effectively unsound horses from the gene pool.

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  • oscar
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Re: Re: speedy gene(s)

13 years 11 months ago
#145285
Fair point SZU howevere the treatment of bleeders legally through a race is getting better and better all the time..I know of "bleeder" fillies that go on to win many races with trainers who know how to train them and get through a race with them...now really do you think a stud farm will not breed with say a six time winner who bleeds a bit?

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  • zsuzsanna04
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Re: Re: speedy gene(s)

13 years 11 months ago
#145340
Oscar,the whole problem is that that is EXACTLY what people do. Which simply perpetuates & exacerbates the problem.

In the good old days when racing & breeding were the playgrounds of the mega wealthy, people bred horses to race themselves & eventually return to stud to improve their breeding programmes.It was therefore in their best interests to strive to improve with every foal.

The famous breeding motto is breed the best to the best. The idea is that each new generation should try to improve on the one that went before. We should be trying to breed better, faster, stronger horses.

However, I don't really know what most people are trying to achieve other than an expensive sale lot. Will it ever run? Once the cheque is safely banked, does anyone really care?

Breeding with a known bleeder is not IMHO 'the best'. Why not rather breed with another good horse that does not bleed?

Quite often good horses do bleed. But by breeding with them, we simply pass the condition on to another generation.

And if we carry on,eventually most of our horses will bleed.

Is that acceptable simply based on the fact that we have the meds to treat it?

The idea behind breeding / racing the THB horse was to create an animal that could carry weight across a distance at speed. Again, to do this you need to create something that is fundamentally sound. Soundness is not only an ethical and moral issue, but an economical one. Horses that are not structurally sound (inside & out) are more prone to injury.Injuries cost money & time off work.

I take a long-term view,which I grant seems a bit unusual for an industry that usually has an attention span of about 2 years! My horses are intended to have a brief track career & then go onto a second career as a sport horse.

As a breeder & a horse lover, I want to produce the best individual I possibly can & I resent the fact that something like furosemide can compromise my horses.

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  • zsuzsanna04
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Re: Re: speedy gene(s)

13 years 11 months ago
#145343
And just before I get accused of saying all breeders are terrible, it is only recent research that has suggested that bleeding is an inherited trait.

If it was merely an exercise-related issue (as people have historically assumed), then treating & breeding with individuals that bleed is a whole different story.

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