april 2005

THE CHIMERA
Don't give animals genes of humans
Mar. 27, 2005
By Jeremy Rifkin

What happens when you cross a human and a mouse? Sounds like a bad joke but, in fact, it's a serious experiment recently carried out by a research team headed by molecular biologist Irving Weissman at Stanford University. Scientists injected human brain cells into mouse fetuses, creating mice that were about % human. Weissman is considering a follow-up experiment to produce mice
whose brains have 100% percent human cells.

What if the mice escaped the laboratory and began to proliferate in the outside environment? What might be the ecological consequences of mice with human brain cells let loose in nature? Weissman says that he would keep a tight rein on the mice and if they showed the slightest signs of humanness, he would kill them. Hardly reassuring.

In a world where the bizarre has become commonplace, few things shock the human psyche. But experiments like the one that produced a partially humanized mouse stretch the limits of human tinkering with nature to the pathological.

This new research field creating hybrid creatures out of different species is at the cutting edge of the biotech revolution and is called chimeric experimentation (after the monster of Greek mythology that was part lion, goat and serpent).

Scientists are looking to break the final taboo in the natural world crossing humans and animals to create human-animal hybrids of every kind and description. Already, scientists have created pigs with human blood running through their veins and sheep with livers and hearts that are mostly human.

The experiments are designed to advance medical research. Many genetic engineers argue that human-animal hybrids will usher in a golden era of medicine. Researchers say the more humanized they can make research animals, the better able they will be to model the progression of human diseases, test drugs and harvest tissues and organs for transplantation into human bodies.

Some researchers are speculating about human-chimpanzee chimeras creating a humanzee. A humanzee would be the ideal laboratory research animal because chimpanzees are so closely related to human beings. Fusing a human and chimpanzee embryo could produce a creature so human that questions regarding its moral and legal status would throw 4,000 years of ethics into utter chaos. If the purpose of creating this hybrid is to perform medical experiments, could those experiments possibly be morally permissible?

Are we on the cusp of a biological renaissance or sowing the seeds of our own destruction?

What scientists fail to mention is that there are other equally promising and less invasive alternatives to these experiments. There's sophisticated computer modeling to study disease and test the effectiveness and toxicity of drugs. There's in vitro tissue culture, nanotechnology and artificial prostheses to substitute for human tissue and organs.

The price of chimeric experimentation is too steep. We should draw the line at this type of experimentation and prohibit any further research into creating human-animal chimeras.


Jeremy Rifkin is the author of "The Biotech Century" He wrote this
for the Los Angeles Times.
http://www.fortwayne.com/mld/journalgazette/news/editorial/11244357.htm