Scientists Create Three Puppy Clones of 'Snuppy,' the World's First Cloned Dog

Courtesy of Nature
Courtesy of Nature

Snuppy, the world's first cloned dog, died in 2015, but his genetic legacy lives on. As the National Post reports, South Korean scientists recently described in the journal Scientific Reports the birth of three clone puppies, all of which are identical replicas of the famous Afghan hound.

Those who lived through the 1990s might remember Dolly, the Scottish sheep that gained fame for being the very first mammal to be cloned from an adult cell. Following Dolly's 1996 cloning, scientists managed to replicate other animals, including cats, mice, cows, and horses. But dog cloning initially stymied scientists, Time reports, as their breeding period is limited and their eggs are also hard to extract.

Ultimately, researchers ended up using somatic cell nuclear transfer (SCNT) to clone a dog, the same method that was used to make Dolly. In the early 2000s, a team of South Korean scientists inserted DNA harvested from an Afghan hound's skin cells into a dog egg from which the DNA had been removed. The egg divided, which produced multiple cloned embryos.

The scientists implanted 1095 of these embryos in 123 dogs, an exhaustive initiative that yielded just three pregnancies, according to NPR. Of these, Snuppy—whose name is a combination of "puppy" and Seoul National University's initials—was the only survivor.

Snuppy died from cancer in April 2015, just shortly after his 10th birthday. To celebrate his successful life, the same South Korean researchers decided to re-clone him using mesenchymal stem cells from the dog's belly fat, which were taken when he was five. This time around, they transferred 94 reconstructed embryos to seven dogs. Four clones were later born, although one ended up dying shortly after birth.

The tiny Snuppy clones are now more than a year old, and researchers say that they don't think that the pups face the risk of accelerated aging, nor are they more disease-prone than other dogs. (Dolly died when she was just six years old, while cloned mice have also experienced shorter lifespans.) Snuppy's somatic cell donor, Tai, lived just two years longer than Snuppy, dying at age 12, the average lifespan of an Afghan hound.

Researchers say that this new generation of Snuppys will yield new insights into the health and longevity of cloned animals. Meanwhile, in other animal cloning news, a Texas-based company called ViaGen Pets is now offering to clone people's beloved pets, according to CBS Pittsburgh—a service that costs a cool $50,000 for dogs.

[h/t National Post]

What Caused Pangea to Break Apart?

iStock.com/alfimimnill
iStock.com/alfimimnill

Emily Devenport:

There's another way to look at this question. People tend to think in terms of supercontinents forming and then breaking up again due to convection currents in the mantle, hot material rising and causing rifts in weaker spots, possibly in old sutures where the continents were shoved together—but what is really happening is that ocean basins are opening and closing, and the ocean has an active role in subduction.

The opening and closing of an ocean basin is called a Wilson Cycle. It begins when hot material rising from the mantle stretches the overlying crust. As molten material rises, a rift is formed. The rift is widened as material continues to squeeze into it. If that rifting goes on long enough, through a broad enough swath of a continent, ocean water will eventually flow into it, and an ocean basin begins to form. The upwelling of hot material will continue to rise through that thinner area of crust, pushing the plates apart. The Atlantic Ocean is an example of a basin that is well along in the Wilson Cycle; eventually subduction is going to begin at its margins, and the whole shebang will pivot.

This will happen because at the edge of continents, sediments accumulate. The weight of those sediments, combined with the weight of the water, drives the heavier, denser edge of the oceanic plate under the continental crust, which is fatter and lighter. Eventually subduction begins, and the basin begins to close again. The Pacific Ocean is an example of a basin that's closing.

If you look at a map of the oceanic rift zones, you'll notice that the one in the Atlantic is pretty much in the middle of that ocean, but the Pacific rift zone has been pulled all the way over to North America above Central America. Subduction is actively occurring on all margins of that plate.

The simple picture is that the continents are moving toward each other across the Pacific Ocean while the Atlantic Basin continues to widen. The truth is more complicated. When plates subduct, the water in the crust lowers the melting point of those rocks, so partial melting occurs. The partially melted material begins to rise through the overlying rocks, because it's less dense, and decompression melting occurs. Eventually, the upwelling of hot material forms plutons and volcanoes above the subduction zones. Fore-arc and Back-arc [PDF] basins can form. As the oceanic crust is pulled under the continental plate, island chains and other chunky bits get sutured to the edge of the continent along with sediments, making it larger. Our world is ~4.6 billion years old, so our continents are really large, now. They're unlikely to rift through the ancient cratons that formed their hearts.

What will happen if subduction begins on the eastern side of North America before the Pacific Basin closes? The margin next to California is a transform fault; it's not subducting. Will it eventually push itself under that part of North America again, or will the transform zone get bigger? The hot spot that was driving the ancient Farallon Plate under North America was eventually overridden by the southwestern states (Arizona, New Mexico, etc.) forming a rift zone. Will it continue to rift or poop out?

There are computer models predicting what supercontinent may form next. They will continue to change as our understanding of tectonic processes gets more accurate.

This post originally appeared on Quora. Click here to view.

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