How Mule Racing Led to Mule Cloning

It was a huge advance in cloning in the early 2000s

Idaho Gem, the first cloned mule, only two days old in this photo but already aww-inducing. Courtesy Phil Schofield/University of Idaho

There are no mule stud farms.

Though mules look sort of like donkeys and sort of like horses, they’re actually a hybrid of the two species, and in almost all cases mules cannot reproduce. That’s one of the reasons why, on this day in 2003, the mule was the first member of the horse family to be cloned, according to The Associated Press. Although mule racing is an accepted sport, it has no great lines of champions the way horse racing does, so it needed another way to keep bloodlines alive.

It was a big victory: According to Helen Pearson for Nature, equines such as mules and horses were difficult to clone using the method that famously produced Dolly the sheep, the first cloned mammal, in 1996. No donkeys were involved in producing the cloned mule, Pearson writes: “The team took DNA from a mule fetus, shot it into a horse egg emptied of its own DNA, and implanted the embryos into mares.” Out of 305 attempts, this one was the first to take, after calcium levels were boosted in the eggs to encourage cells to divide.

The funder for the mule-cloning project was the president of the American Mule Racing Association, Don Jacklin. Jacklin “wanted to bring the world’s attention to racing mules,” lead scientist on the project Gordon Woods told NPR in 2006. Jacklin was also hoping to clone animals from his champion racer, Taz, Woods said. Idaho Gem, the first cloned mule, was part of Taz's line, although not a direct copy of Taz, because he was produced with DNA from a fetus that would have been Taz's brother.

But it’s not like a genetic clone of another animal would be the exact same animal, NPR notes. Anybody who has ever met identical twins knows that genetics are only part of the equation when it comes to individuals. “Cloning is replication, not resurrection,” Woods told NPR. Idaho Gem was “a little bit of a stinker,” he said. The next two, Utah Pioneer and Idaho Star, each had their own personalities as well.   

Idaho Gem and little brother Idaho Star, also a clone, completed their first professional races in 2006. In spite of their different personalities, each won its respective race. That provided important proof that cloned animals could win, according to Wade Goodwyn for NPR.

Although cloned mules have gained acceptance in the mule racing community, that’s far from the case for cloned horses in the racing community. In 2003, mule cloners were considering the possibility that eventually race horses might be cloned as well, which could earn big fees. The expensive and easily injured animals are often castrated to improve their tempers. Cloning race horses could allow a big winner’s line to continue. But nothing has come of that plan—the Jockey Club, which oversees race horses in the United States, won’t even register horses that are the product of artificial insemination, never mind cloning.

But a small horse cloning industry exists in Texas to serve sports, like barrel racing and polo matches, that are outside the purview of the Jockey Club.

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