Some people think their dogs are totally worth constant feeding, walking and Frisbee throwing. Others believe their dogs are worth organic kibble and a permanent place on the bed. To Texas billionaire John Sperling, a dog named Missy was worth cloning.
Starting in 1998, before Missy was even sick, Sperling gave $3.7 million to Texas A&M scientists to fund canine-cloning research [source: MSNBC]. The goal was to clone Missy, described by all involved as an "exceptional" dog. At the very least, she was exceptionally loved.
And so began the research that would become the Missyplicity Project. Some of those Texas A&M scientists formed a commercial venture called Genetic Savings & Clone. Hundreds of pet owners sent in their pets' skin biopsies for storage (for a one-time fee of about $1,000 and a yearly $100 maintenance charge), hoping their beloved pets would eventually come back to them in clone form. The company reports they delivered two cloned cats, but it was taking too long and costing too much money to clone a dog, so it closed in 2006. The business of dog cloning was then transferred to BioArts, a company already established in the areas of livestock cloning and general tissue storage and transport. BioArts created a special pet-cloning division happily called Best Friends Again.
Ten years after the Missyplicity Project began, Sperling was still pumping in money. Considering that mice, cattle, horses, pigs, rabbits, cats and, of course, a sheep had already been cloned successfully, it wouldn't seem like such a tall order to clone a dog. And in fact, it had already been done once by researchers at Seoul National University in South Korea. That dog, named Snuppy, was born in 2005. But one success didn't pave the way for a quick victory in the Missy quest. Dogs might just be the hardest mammal to clone -- even harder than humans.
In this article, we'll find out why it's so hard to clone a dog, whether a dog clone can even be identical to the original, and whether the Missyplicity researchers have succeeded in creating mini Missy's.
First, some background on the insanely complex process of cloning a canine. A dog may be delightfully simple in its needs, but its reproductive system is anything but.
Canine Cloning Is Ruff
Cloning is more common these days than many of us realize. Companies like BioArts do big business cloning cows that have the specific features both ranchers and food consumers want. Horses with exceptional traits are cloned. Sheep have been cloned to re-create animals that grow more wool. The process goes something like this:
- Extract an egg from a donor animal (donor A)
- Remove the nucleus -- which contains the genetic material (DNA) -- from the egg
- Insert a different animal's DNA into that egg (donor B)
- Implant that egg into a surrogate animal for development
The resulting animal should have the DNA of donor animal B, and none of the DNA of either donor animal A or the surrogate.
In its simplest form, those four steps make up the cloning process. It may take a lot of tries to produce a healthy livestock clone (about 90, on average), but it happens regularly enough that companies like BioArts are doing just fine [source: Science News]. The problem is, the specific characteristics of a canine's reproductive system make every one of those steps extraordinarily difficult.
First, there's the very simple problem of lack of knowledge. There has never been any reason for scientists to seek a deep understanding of canine reproduction. So the first issue the Missyplicity scientists had to overcome was a general shortage of research on the subject.
The other problems were far trickier to deal with. First, most animals ovulate on a regular schedule. Human females, for instance, ovulate (release an egg from the ovaries) approximately every 28 days, for about a week. Dogs, on the other hand, ovulate almost at random. It might be every six months, it might be every 18 months. There's no way to know. So scientists have a heck of a time harvesting an egg from a dog.
To make matters even more complicated, dogs don't release a mature egg the way most mammals do. Their ovaries release an immature egg that then develops in the fallopian tubes. Once mature, that egg is viable for a whole two or three hours [source: BioArts]. Extracting that egg from the fallopian tube at the exact right time is a bit of a challenge.
So let's say once a dog starts ovulating, scientists are lucky enough to get to the egg while it's still viable. The next step, removing the nucleus, is a problem, too. Most animals' eggs are translucent, so it's easy to see exactly what's inside and safely extract the nucleus. Dog eggs are opaque, practically black. This makes going in for the nucleus a lot riskier. It requires special equipment to see inside the egg, and it makes for a lot more failed extractions. It also makes it harder to insert the new DNA.
Finally, inserting the prepared egg into a surrogate is a waiting game, too. A dog can only be implanted with a litter when it's in the randomly occurring ovulation period. It's called estrus -- the time period when a dog can become pregnant. Finding a surrogate is just as hard as finding an egg donor.
So how did the South Korean scientists who created Snuppy overcome these challenges? They credit their success at least in part to their work hours. They worked 20-hour days, seven days a week. When a dog in the lab went into estrus, there was someone there to take advantage of it. It only took them three years to produce a viable clone.
Has BioArts had similar success? Are there any little Missy clones running around? Find out on the next page.
Missy donated her DNA, in the form of a skin biopsy, back in 1999, when she was still perfectly healthy. She died in 2002. In late 2007 and early 2008, her clones were born.
It took nearly 11 years and more than $20 million from Sperling, but Missy has at last been immortalized in the form of three puppies [source: TIME]. Both BioArts and the Sperlings say it's not about replication, necessarily. It's also a fascinating experiment in nature vs. nurture. Will Missy's clones act exactly like her, or will the resemblance only be DNA-deep? And more important, will the clones be as healthy as nongenetically-engineered dogs?
According to BioArts, the dogs are perfectly healthy. They have none of the problems that have sometimes plagued clones, like heart and lung issues [source: TIME]. Some say it's too early to tell, though, whether Missy's clones will develop health problems.
A much more happy investigation involves looking for similarities between the clones and the originals. Watching healthy puppies for hours on end isn't exactly a tedious experiment.
Pictures show that the puppies look a lot like Missy. They have the same fur patterns and texture, at least. They're the same breed mix, probably border collie and German shepherd. And they'll probably grow up to look just like Missy.
Personality, of course, is much harder to quantify. Personality in dogs is loosely defined as behaviors, preferences and traits like stubbornness, intelligence and play styles. Missy's clones act, well, like puppies. BioArts does report, however, that the puppies are, like Missy, both intelligent and willful. And, like Missy, they love broccoli, which BioArts says is a very rare trait in dogs (we're skeptical -- see sidebar).
Still, the question is a fascinating one. Just how much of who we are is determined by our genes? How much is a result of environment? The nature vs. nurture debate is nowhere near an end, Missy's clones' love of broccoli aside. And the uncertainty could produce a financial windfall if scientists can find a way to clone pets more efficiently. Recognizing the potential revenue in pet lovers, an international battle has erupted over pet-cloning rights. The two U.S. companies, BioArts and Start Licensing, share the international patent rights to clone household pets. They're now fighting RNL Bio, a South Korean company, tooth and nail to maintain their exclusive right to clone Fido. As of May 2008, RNL Bio has agreed to cease and desist. But some people believe the company is still trying to clone pets on the black market.
For more information on dog cloning, cat cloning and related topics, including how you can sign up to have your little buddy cloned, romp through the links on the next page.
Related HowStuffWorks Articles
More Great Links
- A year later, cloned cat is no copycat. MSNBC.com. November 4, 2003. http://www.msnbc.msn.com/id/3076908/
- BioArts International. http://www.bioarts.com/index.htm
- Cat cloning firm in Marin loses all its nine lives. San Francisco Business Times. October 6, 2006. http://www.bizjournals.com/sanfrancisco/stories/2006/10/09/story5.html?b=1160366400%5E1356912
- Copydog, Copycat. TIME.com. February 11, 2001. http://www.time.com/time/magazine/article/0,9171,98945,00.html
- Missyplicity. Best Friends Again. http://bestfriendsagain.com/missyplicity/index.html
- Molecular Meow Mix Creates Copy Cat Clone. Science News. February 15, 2002. http://www.accessexcellence.org/WN/SU/copycat.php
- Of Copy Cats and Ditto Dogs. Newsday.com. October 16, 2001. http://www.newsday.com/entertainment/nyc-pets-cloning,0,6182463.column
- Real Clone Wars: International Dog-Fight over Cloning Rights. Reuters. June 19, 2008. http://www.reuters.com/article/pressRelease/idUS44186+19-Jun-2008+BW20080619
- Woof, Woof! Who's Next? TIME.com. August 7, 2005. http://www.time.com/time/magazine/article/0,9171,1090890,00.html?iid=sphere-inline-sidebar