hide captionThis mouse egg (top) is being injected with genetic material from an adult cell to ultimately create an embryo and, eventually, embryonic stem cells. The process has been difficult to do with human cells.

Eighteen years ago, scientists in Scotland took the nuclear DNA from the cell of an adult sheep and put it into another sheep's egg cell that had been emptied of its own nucleus. The resulting egg was implanted in the womb of a third sheep, and the result was Dolly, the first clone of a mammal.

Dolly's birth set off a huge outpouring of ethical concern along with hope that the same techniques, applied to human cells, could be used to treat myriad diseases.

But Dolly's birth also triggered years of frustration. It's proved very difficult to do that same sort of DNA transfer into a human egg.

Last year, scientists in Oregon said they'd finally done it, using DNA taken from infants. Robert Lanza, chief scientific officer at Advanced Cell Technology, says that was an important step, but not ideal for medical purposes.

"There are many diseases, whether it's diabetes, Alzheimer's or Parkinson's disease, that usually increase with age," Lanza says. So ideally scientists would like to be able to extract DNA from the cells of older people not just cells from infants to create therapies for adult diseases.

Lanza's colleagues, including Young Gie Chung at the CHA Stem Cell Institute in Seoul, Korea (with labs in Los Angeles as well), now report success.

Writing in the journal Cell Stem Cell, they say they started with nuclear DNA extracted from the skin cells of a middle-age man and injected it into human eggs donated by four women. As with Dolly, the women's nuclear DNA had been removed from these eggs before the man's DNA was injected. They repeated the process this time starting with the genetic material extracted from the skin cells of a much older man.

hide captionDolly, the first mammal to be genetically cloned from adult cells, poses for the camera in 1997 at the Roslin Institute in Edinburgh, Scotland.

Dolly, the first mammal to be genetically cloned from adult cells, poses for the camera in 1997 at the Roslin Institute in Edinburgh, Scotland.

More here:
First Embryonic Stem Cells Cloned From A Man's Skin

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