The idea of creating human-animal hybrids is initially deeply repulsive. Although many people may imagine something out of Planet of the Apes, at least one proposal is less problematic than what it would supplant. The United Kingdom's regulatory agency will make a decision today on whether to permit this practice, which Australia's Parliament recently prohibited.
Stem cell researchers wish to create these hybrids in order to use animal eggs, instead of those from women, in research cloning. Human eggs are in short supply, and their extraction carries health risks. These scientists plan on removing the nucleus from a cow or rabbit egg, inserting the nucleus from a human body cell, and stimulating the resulting hybrid cell to divide into an embryo. Only a tiny portion of the animal DNA would remain. Apart from the occasional crackpot, no one plans on letting these divide for more than a couple weeks, during which the embryo remains an undifferentiated ball of cells. Instead, they'd be destroyed to extract embryonic stem cells with (almost) the same DNA as the donor of the human body cell.
How does this compare with the other option, using human eggs? I'd say favorably, in three ways. First, human stem cells have yet to be successfully derived via cloning. Researchers could investigate and refine the technique using the animal egg alternative. If the results are promising AND human eggs appear to be needed, perhaps scientist could then ask women to provide eggs. Second, if research cloning actually leads to individually-matched cellular therapies (however unlikely they may be), it may be possible to create the patient-matched stem cells using animal eggs. This would dramatically reduce the cost of such therapies. Finally, the hybrid embryos are likely to be less viable than human clonal embryos. This would reduce the chance that research cloning will lead to the abuses of reproductive cloning.
Although this practice may be defensible, some of its backers have crossed a rhetorical line. One applicant for permission to carry out the procedure said:
There are hundreds of thousands of patients in Britain with degenerative neurological conditions. We can use these cell lines to study them, and to see if drugs are going to be effective. To shut that down is a real affront to patients who are desperate for therapy. Of all these diseases, none are really treatable. This is a very serious turning point in terms of science and medicine.This appeal to our greatest hopes, and worst fears, is gratuitous emotional manipulation. There are no therapies from any embryonic stem cell lines, and such stem cell lines have yet to be successfully derived via cloning. Political actors occasionally "play the fear card" in debates, such as those over the prevent of terrorism. Both biomedical research and anti-terrorism efforts should be supported, but the development of policy should be reality-based, not excessively speculative and emotional.
Posted in Hybrids & Chimeras, Jesse Reynolds's Blog Posts, Research Cloning, Stem Cell Research, The United Kingdom
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Comment by Thoughtful, Jan 13th, 2008 2:00pm
Uh, is that a real picture? It's terrifying.