Creating human-animal chimeras in the laboratory

Creating human-animal chimeras in the laboratory

Early embryonic cells of any species are usually
accepted by another organism, even if that other
organism belongs to a completely different species. I
believe I read that stem cells from a chimpanzee
embryo could conceivably be injected into an adult
human being and in many cases grow and not be rejected
by the immune system of that adult human being.

Faulty human heart valves are routinely replaced with
ones taken from cows and pigs. Such a routine surgery
makes the recipient of that valve a human-animal
chimera. And for years scientists have created other
types of chimera as well, adding human genes to
bacteria to make them produce human insulin, even
adding human genes to farm animals.

What's caused the uproar is the mixing of human stem
cells with embryonic animals to create new species.

The latest news is this:
http://news.nationalgeographic.com/news/2005/01/0125_050125_chimeras.html

Chinese scientists at the Shanghai Second Medical
University in 2003 successfully fused human cells with
rabbit eggs. The embryos were reportedly the first
human-animal chimeras successfully created. They were
allowed to develop for several days in a laboratory
dish before the scientists destroyed the embryos to
harvest their stem cells.

In Minnesota last year researchers at the Mayo Clinic
created pigs with human blood flowing through their
bodies.

And at Stanford University in California an experiment
might be done later this year to create mice with
human brains.

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Received on Tue Mar 29 22:57:46 2005