This I find more than a bit disturbing....
SAN FRANCISCO - Add another creation to the strange scientific menagerie where animal species are being mixed together in ever more exotic combinations. Scientists announced Monday that they had created mice with small amounts of human brain cells...Read it here.
[T]he researchers created the mice by injecting about 100,000 human embryonic stem cells per mouse into the brains of 14-day-old rodent embryos.
[T]he work adds to the growing ethical concerns of mixing human and animal cells when it comes to stem cell and cloning research. After all, mice are 97.5 percent genetically identical to humans.
"The worry is if you humanize them too much you cross certain boundaries," said David Magnus, director of the Stanford Medical Center for Biomedical Ethics.
Researchers are nevertheless beginning to bump up against what bioethicists call the "yuck factor."
Three top cloning researchers, for instance, have applied for a patent that contemplates fusing a complete set of human DNA into animal eggs in order to manufacturer human embryonic stem cells.
One of the patent applicants, Jose Cibelli, first attempted such an experiment in 1998 when he fused cells from his cheek into cow eggs.
"The idea is to hijack the machinery of the egg," said Cibelli, whose current work at Michigan State University does not involve human material because that would violate state law.
Researchers argue that co-mingling human and animal tissue is vital to ensuring that experimental drugs and new tissue replacement therapies are safe for people.
Others have performed similar experiments with rabbit and chicken eggs while University of California-Irvine researchers have reported making paralyzed rodents walk after injecting them with human nerve cells.
Doctors have transplanted pig valves into human hearts for years, and scientists have injected human cells into lab animals for even longer. But the brain poses an additional level of concern because some envision nightmare scenarios in which a human mind might be trapped in an animal head.
I take the "yuck factor" very seriously. It is a marker of social consensus -- something that should always be considered by those who would make public policy, even [perhaps especially] in matters that touch boundaries of scientific knowledge. Science policy is too important to be left to the scientists.
And what might be the outcome of genetic mixing between humans and rodents? Check out the picture above.