Scientists in Italy say they have created the world's first cloned horse, raising the possibility of a sequel to the next Seabiscuit (search) or a carbon copy of Kentucky Derby champion Funny Cide (search).
The small, sturdy work horse is now two months old, weighs about 220 pounds and is in excellent health, said its creators. Their announcement beats a Texas A&M team awaiting the birth of its own horse clone.
In a twist for the growing barnyard of cloned animals, the Haflinger mare that gave birth to the Promotea was also the source of her DNA, meaning she and her foal are identical twins.
Now that horse-cloning has arrived, it could allow the replication of valuable horses or endangered breeds, said Cesare Galli, director of the Laboratory of Reproductive Technology in Cremona, Italy.
"The most obvious use is to give a sterile animal or animals that die or can't breed because of some disease a chance to reproduce," Galli said.
The cloning details are described in Thursday's issue of the journal Nature.
Prometea was born just two weeks after the first member of the equine family — a mule — was cloned at the University of Idaho. Researchers there have since produced two more cloned mules, which are a hybrid of a donkey and a horse.
Scientific differences in the two cloning projects are striking.
The mules were cloned from cells extracted from developing mule fetuses. But Prometea's DNA came from her adult mother's skin cells. Cloning adult DNA has proven more difficult than copying fetal DNA.
There were other differences. The Idaho team harvested fertile eggs, one at a time, from mares. They then removed the nucleus of each egg and inserted DNA from cells of a mule fetus. Those reconstructed eggs were surgically implanted into the wombs of female horses.
Galli's team, however, harvested hundreds of eggs from mare carcasses at a slaughterhouse. They cultured the eggs, removed their DNA and replaced it with DNA taken from either adult male or female horse skin cells.
Out of a total of 841 reconstructed embryos, only 22 developed to advanced embryos within about a week. Seventeen of those were introduced into nine mares, resulting in four pregnancies, but only one, Prometea, developed to full term.
It was delivered naturally and unassisted on May 28.
To date, horses, mules, sheep, cows, pigs, cats and rodents have been cloned. No primates have been cloned. Their cases have raised questions about clones' health.
Dolly the sheep, the first cloned mammal, was euthanized this year after she contracted a common livestock disease and her cells showed signs of premature aging.
Gordon Woods, who led the University of Idaho mule-cloning team, said the successes in cloning equines could open the door to cloning racing champions, or horses with other sought-after traits.
For example, Funny Cide, the winner of both this year's Kentucky Derby and Preakness races, is a gelding, or a castrated male.
Geldings were widely thought to be uncompetitive. Funny Cide otherwise would've been a lucrative stud horse. Cloning him would keep his champion genes in play.
"If one could clone Funny Cide, the clone of him could be the stud. He could pass on the genetics," Woods said.
But Texas A&M research veterinarian Katrin Hinrichs, leader of the rival horse cloning group, said clones would be rejected by the Jockey Club, which registers thoroughbred horses.
Hinrichs is awaiting the birth of a cloned American quarter horse — a copy of Hinrichs' 9-year-old daughter's show horse — in mid-November. She believes cloning's most obvious use in the horse industry would be cloning such show horses.