US scientists have cloned a monkey, using the resulting embryos to grow valuable stem cells. The development is the first time a primate embryo has been created, leading experts to speculate that it's a matter of time before human embryos are cloned to treat disease. VOA's Jessica Berman reports.
Researchers at Oregon Health and Science University used the DNA of skin cells from rhesus macaque monkeys to create embryos from which they extracted stem cells three days later.
In earlier research, the team successfully cloned mouse embryos.
Stem cells are master cells that scientists say can be coaxed to grow into any tissue in the body, making them valuable as a tool for potentially treating or curing human disease.
Robert Lanza is chief of Advanced Cell Technology, a biotechnology firm in Massachusetts.
Lanza says the achievement marks a major milestone in genetic research.
"It's enormously important and a giant step toward showing that human therapeutic cloning is indeed possible," he said. "And it proves once and for all that primate cloning is not impossible as everybody thought."
Observers say it's taken a long time to clone a primate embryo because researchers have had to overcome a variety of genetic challenges.
In a study published in the journal Nature, researchers describe how they used 304 eggs from 14 rhesus monkeys before they succeeded in creating two embryos from which they grew the two stem cell lines.
Supporters of therapeutic stem cell research say the goal is not to make identical copies of animals, but to create embryos so organs can be grown from scratch using the stem cells.
Experts say the tissue grown from embryonic stem cells could potentially provide desperately needed organs to people who need transplants. They say such organs could also be matched to the recipient so the transplanted organ is not rejected.
Lanza says the fact that a primate embryo has now been created means the cloning of a human embryo is a virtual certainty.
"I think the race indeed is on for cloning human embryos for generating patient specific cells. Of course, nobody in the field wants to clone an entire human being," he added. "So, it's only going to be a matter of time before you see a paper showing that this works in humans."
The field of embryonic stem cell research has been marked by controversy. South Korean scientist Hoo Suk Hwang claimed falsely in 2004 to have created the first cloned human embryos, setting back the field.
And in the United States, opponents, led by President George W. Bush, feel strongly that it is wrong to use human embryos in this way. The opposition has led Mr. Bush to block attempts to expand federal funding for embryonic stem cell research.