Tonight I ask you to pass legislation to prohibit the most egregious abuses of medical research: human cloning in all its forms, creating or implanting embryos for experiments, creating human-animal hybrids, and buying, selling, or patenting human embryos.Christianity Today considered this "what may prove to be the most profound paragraph in the State of the Union address." It specifically looked at the chimera phrase:
The third abuse is making a human-animal "hybrid" or "chimera." This is a being that is part-human, part-animal. Scientists have already been playing around with genes, switched from one animal (or plant) to another. The same principles could be used on humans. One team wants to use rabbit eggs to provide a home for human DNA, to make an embryo that is mostly human but a tiny bit rabbit—in order to kill it for stem cells. All of these Frankenstein efforts must be stopped in their tracks.The transfer of genes between species is indeed done frequently by scientists, as it is a very valuable technique for many kinds of research.
Many genes are highly conserved among species. Essentially the same gene is found in different species. That is, the sequence of nuclaic acids is very similar in genes from one species to another. It is the genome, the entire sequence of genetic information that makes the difference.
A metaphore: all writers in the English language should spell words the same way. It is the order of words in a work that distinuishes one piece of writing from another. Indeed, cognates are words that are spelled the same way or in very similar ways in different languages. Sometimes we use a term from another language if it is apropos.
P. Z. Myers writes in Pharygula, "Creating chimeras is legitimate and useful scientific research."
Down syndrome is a very common genetic disorder caused by the presence of an extra chromosome 21. That kind of genetic insult causes a constellation of problems: mild to moderate mental retardation, heart defects, and weakened immune systems, and various superficial abnormalities. It's also a viable defect, and produces walking, talking, interacting human beings who are loved by their friends and families, who would really like to be able to do something about those lifespan-reducing health problems. We would love to have an animal model of Down syndrome, so that, for example, we could figure out exactly what gene overdose is causing the immune system problems or the heart defects, and develop better treatments for them.Similarly, William Weir writes in the Hartford Courant
So what scientists have been doing is inserting human genes into mice, to produce similar genetic overdoses in their development. As I reported before, there have been partial insertions, but now a team of researchers has inserted a complete human chromosome 21 into mouse embryonic stem cells, and from those generated a line of aneuploid mice that have many of the symptoms of Down syndrome, including the heart defects. They also have problems in spatial learning and memory that have been traced back to defects in long-term potentiation in the central nervous system.
These mice are a tool to help us understand a debilitating human problem.
Most examples of chimeric research (from "chimera," the Greek word for a goat/lion/serpent combination) don't look like strays from Dr. Moreau's island. At Stanford University researchers injected human brain cells into the brains of mice. The researchers also plan to develop a mouse with 100 percent human brain cells. Though they doubt it would develop human characteristics, researchers say they would terminate the project at any sign that it would.Clearly President Bush wants to prohibit something to do with genetic transfer, and apparently some on the religious right support such a ban, but it is not clear to me what is to be banned, and why.
Similar experiments have been conducted elsewhere for research on Parkinson's disease and other neurological disorders.
When in 2001 Bush banned use of new lines of stem cells in research, the initiative was apparently badly staffed out, and his information on the number of stem cell lines available has proven false. The majority of Americans now seem to feel that the stem cell lines can be derived ethically, and that the potential scientific and medical benefits from a vigorous program of stem cell research justify the work. Is Tuesday's announcement similarly poorly staffed out? Is it likely to result in legislation that will be ultimately disavowed by the public, but that will slow important research during its lifetime?
The Bush Administration has used the State Department to push its agenda on stem cell and related research in international fora. Is it now likely to push a ban on "human-animal hybrids" internationally? I hope not!
2 comments:
Should this research be allowed or banned?
What is your opinion?
I certainly would allow a lot of research that involved introducing genes from human cell lines into other species, introducing genes derived from other species into human cell culture. As I understand it, there is useful work that involves growing human cancer tumors in mice (which would technically make the mice chimeras). The research desctibed above on Downs syndrome and Parkinson's disease seem useful and acceptable.
Of course there are limits. I would not accept creating a chimera embrio with human and non-human cells to be implanted in a woman. It seems quite appropriate that there be new regulations for research newly possible in human reproductive biology.
And indeed, in our democratic society, there is a role for debate on the ethics of the limits to be imposed. Of course, in our society, many will enter that debate based on their religious views.
But there is a real risk. Many in our society don't believe in evolution. Their grasp of modern science is weak beyond belief. I don't want U.S. policy to be based on superstitious beliefs of the scientifically uninformed. The potential benefits of research in these areas are too great to sacrifice to ignorance or to those who would pander to the ignorant for short term political gain!
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