WHILE reproductive cloning of animals isn鈥檛 anything like as controversial as the idea of trying to clone humans, it still evokes strong feelings. Cloning livestock promises to bring us better food, but will anyone eat it? Cloning endangered species is an option only if the animal concerned has a closely related farmyard counterpart to supply eggs and act as a surrogate. And cloning pets is just for the sentimental with more money than biological understanding.
But one application that has received less attention shows a surprising amount of promise: cloning sport horses. These are the animals that compete in events such as dressage, cross-country and show jumping. The very idea will undoubtedly raise eyebrows, but there are several reasons why this practice could become commonplace sooner than any of the others.
For a start, there are no rules outlawing the cloning of sport horses. This is in marked contrast to racehorse organisations around the world, which make it quite clear that cloning thoroughbreds for racing is not on.
Advertisement
Secondly, there is a genuine need for this technology. Almost all sport horses are geldings 鈥� castrated males. Mares make an occasional appearance, but intact stallions rarely do. They tend to have their minds on other things and a mistimed jump can lead to a nasty testicular bashing. This puts championship-winning sport horses in the rather strange position of being unable to reproduce the special set of genes that helped them win, and leaves their owners unable to create a lucrative dynasty of champions. Cloning is their only reproductive hope.
There may also be something about the biology of horses and other equids that makes them particularly well suited to cloning. In several species 鈥� notably ruminants such as sheep and cattle 鈥� cloned offspring often have poor health and die young. But the few cloned equids born so far are all doing fine. The jury is still out on why this is, but it could be because of differences in the way the placenta develops.
Whatever the reason, the higher success rates give this application serious commercial promise. Several laboratories are now offering to 鈥渂ank鈥� cells from prize-winning sport horses for owners who want to keep their cloning options open. And at least two companies are already offering to go ahead and clone.
Cryozootech, a French company based in Sonchamp near Paris, already has cells stored from more than 30 horses and will guarantee its customers a single clone for a mere 鈧�300,000. Earlier this year, Cryozootech produced clones from two prize-winning sport horses in collaborations with scientists in Italy and at Texas A&M University.
Another venture, horsecloning.com, involves the scientists at the University of Idaho who created the world鈥檚 first equine clone back in 2003, a mule called Idaho Gem. For a similar sum to Cryozootech鈥檚 scheme, the company will transfer cloned embryos to 100 mares. Although there is no guarantee of success, it claims this could produce as many as 16 genetically identical foals. An innovative royalty scheme that forms part of the package means that not only could an investor come away with several valuable horses, they would also stand to reap further financial rewards if they sell any of the clones and these horses are then bred from or subsequently cloned.
Cloning is still a relatively inefficient and hence costly procedure. Things have improved since Dolly the sheep鈥檚 day, but not a lot: dozens of donor females are still needed to supply hundreds of eggs from which to fashion enough embryos to give a reasonable chance of the birth of just one clone. Though this makes financial sense for the most valuable sport horses, most owners are priced out of the market.
But there are signs that this is changing. The Idaho mule-cloning team used around 300 eggs and managed three pregnancies that lasted beyond the early stages in which an embryo is most likely to die. Just a couple of years on, refinement of the cloning technique by the Texas A&M team has resulted in more than four times the number of pregnancies from a similar number of eggs. If this rate of progress continues, the price of cloning may tumble, and if that happens it could become an attractive option to many more owners.
鈥淭here may be something about the biology of horses and other equids that makes them well suited to cloning鈥�
There will be opposition, most obviously from those uncomfortable with the inefficiency of the cloning process. In the UK, for example, such concerns have led to a government ban on cloning sport horses for commercial purposes. Cloning for research purposes is in theory allowed, though no one has yet applied to do it. In other countries there is little to stop the advance of the would-be equid cloners. And while most cloned horses will be destined to breed rather than to compete, competition is surely something that some owners will find hard to resist.
So before so much as a morsel of cloned meat makes it onto a supermarket shelf, and before reproductive cloning achieves anything significant for the conservation cause, cloning could take off for sport horses. It would not be that surprising if we find clones of champions strutting their stuff on the showground.
