University still has no plans to clone embryos

While scientists at Harvard University have requested permission from the school’s ethics boards to create cloned human embryos for stem cell research aimed at finding cures for numerous diseases, the dean of the Yale School of Medicine said cloning will not be a part of the stem cell research at the University in the near future.

Harvard Stem Cell Institute co-director Douglas Melton and biologist Kevin Eggan have asked to perform somatic cell nucleic transfer — the insertion of a body cell containing a person’s DNA into an unfertilized egg — to create embryonic clones, from which undifferentiated stem cells can be harvested and used to study diseases. But, because the embryos are destroyed in the process, this practice has raised controversy among some who believe it is tantamount to murder.

Yale Medical School Dean Robert Alpern said the University’s research would begin on embryonic stem cells already in existence.

“We could use pre-existing cloned cells,” Alpern said.

So far, the only successful attempt to harvest stem cells from cloned human embryos was made by South Korean scientists earlier this year.

Another team of Cambridge-based researchers, Dr. George Daley of the Harvard-affiliated Children’s Hospital and fellow doctor Leonard Zon, will also seek permission to perform stem cell research to examine blood diseases and immune deficiency, Daley said. He said the embryos used to obtain stem cells would consist of 60 to 200 cells and would exist in cultures scientists would maintain for only a short period of time.

“If the intention is not to implant the embryos, they have no future,” Daley said.

He said there is a strong need to create embryonic clones for stem cell experiments, in addition to the current practice of using existing stem cell lines taken from embryos left over at fertility clinics.

“This will allow us to do very important medical research that we can’t do with existing cell lines,” Daley said. “It will allow us to ask and answer very different questions, to use lines with genetic information from patients with specific diseases.”

Yale biology professor Weimin Zhong, who has performed research on neural stem cells in mice, said if he were able to use human cells in his research, he would.

“I think we absolutely should encourage the use of human stem cells,” Zhong said. “This is an emerging field, with many questions still to be answered. At the end of the day, a ball of cells is not a human being.”

But David Stevens, the executive director of the Christian Medical Association, said he believes the creation of embryonic clones for stem cell research is morally and scientifically wrong and said it was a form of “human sacrifice.”

“It is wrong to create human beings for the purpose of research,” Stevens said. “Every one of us was once an embryo. To say an embryo is just a potential human being is disingenuous.”

Stevens said adult stem cells are useful in experimental research for curing disease as an alternative to embryonic stem cells. He also said the process of creating and maintaining embryonic cell lines would be impractical and costly.

“Let’s say we could cure diabetes,” Stevens said. “Then the need for human eggs would be overwhelming. That also could have ethical implications for women here and in other countries.”

According to the National Institutes of Health Web site, there are limitations to using adult stem cells in research. Adult stem cells are often difficult to isolate and purify, and do not have the potential to form as many types of tissues as embryonic cells.

In 2001, President George Bush issued an executive order banning federal funding for research on new embryonic stem cell lines. The Harvard research is privately funded.

Images chart the development of an embryo in its first, third and fifth days of development, respectively. Stem cell research uses cells derived from these blastocysts.
Courtesy DennySakkas
Images chart the development of an embryo in its first, third and fifth days of development, respectively. Stem cell research uses cells derived from these blastocysts.

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