Medical Breakthrough or Monstrosity?

“Scientists have begun blurring the line between human and animal by producing chimeras—a hybrid creature that's part human, part animal.”
Mary Ann Mott, National Geographic News


According to Reuters UK ( “Factbox: Human Fertilisation and Embryology Bill” ), controversial medical research innovations are being debated in Parliament’s House of Commons this week. The Human Fertilisation and Embryology Bill raises several interesting bioethical issues, one of which would allow the creation of human-animal hybrid embryos to be used for medical research.

Interspecies embryos would be created by taking a cell from a patient and inserting it into an enucleated animal ovum. An electric shock would fuse the two cells together allowing the formation of an embryo. Because the genetic material from the animal has been removed, the resulting embryo would be 99.9% human and an excellent model for medical research. The proposed legislation mandates that these embryos must be destroyed before 15 days, and they must not be implanted into the uterus of a woman or another animal.

The advantage of creating mixed-species embryos is that they can be a powerful research tool for developing stem cell models without the use of human eggs. Embryonic stem cells would be taken from the new hybrid embryo and injected into specialized human tissues, giving researchers insight on understanding the progression and possible treatment of medical conditions such as Alzheimer's disease, cystic fibrosis, Parkinson’s disease, diabetes, and other inheritable diseases. Stem cells could also be used to repair human tissue by allowing new tissue that is genetically matched to the individual to be cultivated for damaged body parts without the risk of rejection.

Scientists and researchers are excited about the medical possibilities that may unfold, and supporters of this bill are convinced that these techniques are “an inherently moral endeavor” that could eventually save millions of lives. There is, however, a great deal of public anxiety about the ethics of experimenting across species boundaries. Many critics find it unnatural and morally wrong to combine human and animal genetics. They also question the benefits of hybridization, claiming that there is no evidence that this will help cure diseases and that other research methods are more effective. They find it both misleading to the public and an abomination to nature. “There are other ways to advance medicine besides going into the strange, brave new world of chimeric animals.”

Even scientists are divided on this issue. Although there may seem to be medical advances to be gained from human-animal hybridization, we really need to make sure that these benefits outweigh the possible risks. In the words of William Cheshire, associate professor of neurology at the Mayo Clinic’s Jacksonville, Florida branch,


“We must be cautious not to violate the integrity of humanity or of animal life over which we have a stewardship responsibility. Research projects that create human-animal chimeras risk disturbing fragile ecosystems, endanger health, and affront species integrity.”



[Photo courtesy of goatboyfilms.com/.]

We're Not Monkeying Around (or are we?)

[Cross-posted from blog.bioethics.net]:

After what it calls "a series of detailed deliberative sessions", Britain's Human Fertilisation and Embryology Authority gave the go ahead Wednesday for the creation of embryos that would contain both human and animal cells. Such research is banned in Canada and President Bush has called for it to be forbidden in the US*. Here's more from HEFA's statement:

Having looked at all the evidence the Authority has decided that there is no fundamental reason to prevent cytoplasmic hybrid research. However, public opinion is very finely divided with people generally opposed to this research unless it is tightly regulated and it is likely to lead to scientific or medical advancements.

This is not a total green light for cytoplasmic hybrid research, but recognition that this area of research can, with caution and careful scrutiny, be permitted. Individual research teams should be able to undertake research projects involving the creation of cytoplasmic hybrid embryos if they can demonstrate, to the satisfaction of an HFEA licence committee, that their planned research project is both necessary and desirable. They must also meet the overall standards required by the HFEA for any embryo research.

There are already two applications for human animal chimeric embryo research before the regulatory panel. The applications include proposals to inject human DNA into the embryos of cows or rabbits, ultimately in an effort to produce stem cells.

The May 2007 AJOB Neuroscience featured a target article about the proposed human neuron mouse. This summer Hank Greely, one of the target article's authors, and Francoise Baylis, who authored a peer commentary, both appeared on a bioethics.net podcast to talk about the ethical implications of human-animal chimeras.

-Greg Dahlmann

*Or, at least, we think he did. In the State of the Union Address, Mr. Bush used the term "hybrid" which isn't the same thing as a chimera. US Senator Sam Brownback (R-KS) has proposed legislation to ban human animal chimeras (the bill actually uses the word) and apparently the President supports this legislation.

The Church: Chimera embryos have right to life

From the UK and the Telegraph: Under proposed legislation to be debated by Parliament later this year, scientists will be given permission for the first time to create chimeric embryos for research as long as they destroy them within two weeks. But the Roman Catholic Church opined that human-animal hybrid embryos conceived in the laboratory - so-called “chimeras” - should be regarded as human and their mothers should be allowed to give birth to them:
"The bishops, who believe that life begins at conception, said that they opposed the creation of any embryo solely for research, but they were also anxious to limit the destruction of such life once it had been brought into existence. In their submission to the committee, they said: 'At the very least, embryos with a preponderance of human genes should be assumed to be embryonic human beings, and should be treated accordingly.'"

For the full article, click here.