A renowned U.S. stem cell expert says he doubts professor Hwang Woo-suk's paper on the world's first cloned dog "Snuppy" that was released in August.

In a phone interview with the Japanese daily Yomiuri Shimbun Sunday, the medical director of Advanced Cell Technology magazine Robert Lanza said he has evidence that Hwang's paper on Snuppy has several flaws.

Lanza said an independent investigative body of American and European experts should verify both Hwang's paper on stem cell research published in July and the thesis on Snuppy.

In August, Hwang and his team showed a five-month-old hound whose genes they said came from a single cell taken from the ear of an adult Afghan rather than the egg and sperm of a mother and father.