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Is Snuppy the Puppy for Real?
With Hwang's scientific credibility in shambles, the status of the world's
most famous dog hangs in the balance. The embattled scientist maintains that
Snuppy is the world's first canine clone, and he even hired an independent
Korean DNA lab, Human Pass Inc, to verify that assertion. The verdict: Human
Pass CEO Seung Jae Rhee told TIME last week, "There is no dispute about these
results, and so I am 100% certain on Snuppy's authenticity." But since Human
Pass is in essence working for Hwang, that's hardly good enough for the
investigative panel at Seoul National University, which is carrying out
independent tests, or for the editors of Nature, who have ordered an
investigation.
If Snuppy really was cloned from the ear cell of a 3-year-old male Afghan
named Tai, it shouldn't be tough to prove, even to those outside investigators.
As long as they have tissue samples from both the clone and the parent, they
should be able to determine whether DNA in the nuclei of both animals' cells is
identical-the first hallmark of a true clone.Ian Wilmut, the Scottish scientist
who created Dolly the sheep in 1996, had to provide such samples to prove to
skeptics that he had created history's first mammalian clone.
Even with the controversy raging over his stem-cell paper, Hwang could have
forestalled some of the questions about Snuppy if he had offered one additional
bit of confirming proof in his original paper in Nature. That piece of critical
evidence comes from the animals' mitochondria, tiny energy-producing structures
within each cell. While most of a mammal's DNA resides in the nucleus, there's
also some in the mitochondria. (Nuclear DNA forms the animal's basic genetic
blueprint; mitochondrial DNA contains instructions for making proteins involved
in various metabolic functions within the cell. )
Mitochondrial DNA is passed down from the mother as gart of the egg's
genetic contribution. Identical twins, for example, have the same nuclear and
mitochondrial DNA,since they're produced when a single egg is fertilized and the
resulting embryo splits in two.With a clone, the situation is different. Because
the cloning process that Hwang says he used to create Snuppy involves two
dogs-one for the nucleus and another for the egg-Snuppy's mitochondrial DNA
should not match Tai's. That's what Rhee's scientists say they've found and what
Hwang undoubtedly hopes the university and Nature will find as well. Final,
ironclad proof of Snuppy’s provenance would involve showing that the dog's
mitochondrial DNA matches that of his egg donor .It's not clear, however,
whether that test is being done.
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