On November 25, 2001, a Massachusetts biotechnology company, Advanced Cell Technology (ACT), reported in an online journal¿e-biomed: The Journal of Regenerative Medicine¿that it had cloned the first human embryos. In a concurrent article in the January Scientific American, the researchers explained that their results could "represent the dawn of a new age in medicine by demonstrating that the goal of therapeutic cloning is within reach." Therapeutic cloning¿in contrast to reproductive cloning, intended to create a baby¿would produce the stem cells needed to treat diabetes, paralysis and other currently incurable conditions.

Image: MELISSA SZALKOWSKI

Many leading scientists, however, say the work should never have been published, because the research failed on several accounts to achieve its goals. First, ACT didn¿t produce any stem cells. But more fundamentally, some investigators questioned the company¿s basic assertion about having actually cloned a human embryo. In the experiment, the ACT researchers injected cumulus cells into eggs that had their nuclei removed. (Cumulus cells nurture eggs in the ovary.) The investigators hoped that the cumulus cells¿ DNA would launch the process of early embryonic development that leads to a hollow sphere called a blastocyst, which would contain stem cells. Among the eight eggs injected with cumulus cells, two divided until they became four-cell embryos, and one proceeded until it reached six cells. Eleven other eggs injected with the nucleus of a skin cell failed to develop.

According to some biologists, a cloned embryo would attain its true status as an embryo only when the DNA from the cumulus cell transferred into the egg began transcription (in which its genes begin to issue instructions to make proteins for embryonic development). An egg contains genetic material (RNA) and proteins that were made during the formation of the egg within the ovary and can support development up to the eight-cell stage without any signals from the DNA in the nucleus. Thus, the ACT experiment may have been "running on fumes, purely directed by RNA and supported by proteins that were present in the egg," says John Eppig, a developmental and reproductive biologist at Jackson Laboratory in Bar Harbor, Me. Eppig adds that "there¿s no published information on a cloned human embryo. Whether someone has done it and not published it, your guess is as good as mine. This [result] is not it." (There was one previous claim of multicell embryo clones, but the findings were not published.)

Eppig is not alone. "They did not present in their paper any evidence that the nuclei that they transferred into the eggs were biologically active," notes Brigid Hogan, a developmental biologist at Vanderbilt University and a member of a National Academy of Sciences panel examining the scientific and medical aspects of human cloning. "So therefore, strictly speaking, they cannot say they generated a cloned embryo." She goes on to say, "If that had been [about anything but] human embryos, it would have never gotten accepted in any journal whatsoever, and I¿m not the only one that thinks that. I mean, they should have kept quiet until they got some results that were worth publishing." Rudolf Jaenisch, a cloning expert at the Whitehead Institute for Biomedical Research at the Massachusetts Institute of Technology, concurred: "It¿s shocking to me that this would be published and that they would have attempted to publish; it¿s the total failure of an experiment."

Paul Berg, professor emeritus of biology at Stanford University and a Nobel laureate, also expressed his outrage: "It was anything but a reportable result. I have not heard a single person in this field who hasn¿t rolled his eyes and been extremely puzzled of what the motive for it was. Anyone who wasn¿t totally naive would have predicted that this would have raised a firestorm among the people who were trying to prohibit this research." Harry Griffin, assistant director at the Roslin Institute, which cloned Dolly the sheep, also questioned whether the work should have been published. But Griffin asserts that, even if the work eventually proves a success, it would be impractical as a routine technique for cell therapy. "The suggestion that the cloning of an embryo would revolutionize stem cell therapy by providing a route for routine immunocompatible cell transplants is simply naive. Such a treatment might be possible for a small number of patients, but there are five million suffering from Parkinson's disease in the U.S. alone. There is, in our view, no way that individual embryos can be created to provide individual treatment for this number of people¿it would be incredibly costly, and there are simply not enough human eggs available."