Snuppy rewards dogged approach
Canine eggs are tough to crack, but clone finally survives.
The first duplicate pooch ambles on to the world stage today. His birth was a feat of ingenuity and perseverance, but some scientists question the value of the exercise.
The Afghan hound puppy has been hidden from the world at the Seoul National University in South Korea for the nine weeks since his birth from a yellow Labrador retriever. He bears exactly the same DNA as an older hound who lent a few ear cells to the researchers.
He's also quite a survivor, being the only one of 1,095 cloned embryos implanted in 123 dogs to survive to healthy puppyhood.
Seoul National University, South Korea
Cloning animals has proven difficult and every species presents its own problems. Even when everything seems to be going right, the majority of cloned embryos fail because their genes are expressed in abnormal ways.
For dogs, the main challenge lies in harvesting the eggs. Canine eggs leave the ovary at a very early stage of development and then mature as they travel towards the uterus in the oviducts.
Harvesting the eggs at the point of ovulation and trying to mature them in a test tube failed. So the research team had to wait and remove the eggs by flushing them out of the oviducts using a custom-made solution.
The nucleus of each of these egg was removed and replaced with a nucleus from an ear cell. Successfully fused cells were then implanted in female dogs.
The painstaking work was completed by the lab of Woo Suk Hwang, the South Korean researcher who is famous for creating a cloned human embryo and deriving stem cells. The lab's dog work is reported in this week's Nature2.
It took a team of about 15 people two-and-a-half years to produce the dog, whose name 'Snuppy' is short for Seoul National University puppy.
"He is very cute. If you come here, if you meet him, you may fall in love with him," says Hwang, who adds that while the puppy looks exactly like the somatic cell donor, it's still unclear whether their personalities are similar.
The donor dog belongs to a professor of internal veterinary medicine at the university, but the puppy "belongs to all human beings, not to myself or the somatic-cell-donor owner", says Hwang.
Barking up the wrong tree?
Hwang says the point of bringing Snuppy into the world is to pave the way for a line of dogs that could model certain human illnesses. But cloning a kennel of diseased canines is a long way off, according to Mark Westhusin, a reproductive biologist at Texas A&M University, College Station, who is famous for cloning a cat2.
Westhusin and his team spent three years trying to clone a dog before they threw in the towel. He says the Korean sucess, while wonderful, may not have been worth it.
"It's a logistical nightmare to work with this species. We've known and predicted for years that it was feasible. It's just, how much time and money and effort do you want to devote to the project?"
Westhusin would like to see work done that would make the process easier, such as the development of a hormone treatment to induce canine ovulation, or a method for maturing eggs in a test tube.
The current work impresses him more for its single-minded tenacity than for its novelty. "They're an outstanding lab and I'm happy for them, but all this says is that you can clone a dog, which we've basically known for some time."
- Lee B. C., et al. Nature, 436. 641 (2005).
- Shin T., et al. Nature, 415. 859 (2002).