c. 2006 Religion News Service

(UNDATED) Examples of chimera research projects as compiled by the Center for Bioethics at the University of Minnesota:

_ Sheep/human chimeras

Researchers at the University of Nevada at Reno added human stem cells to sheep fetuses in an attempt to create a reliable source of livers for transplant patients. Some sheep have livers with up to 80 percent human cells that produce compounds made by human livers. The sheep also have human cells in their hearts and brains.

_ Pig/human chimeras

Researchers at the Mayo Clinic in Minnesota are studying specially bred pigs as a source of organs for human transplant. They are also studying the risk of transmitting pig diseases to humans through the organs. They have developed a line of pigs that have pig blood cells, human blood cells and hybrid blood cells.

_ Mice with human brain cells and immune systems

Researchers at Stanford University have injected human neural stem cells into mouse fetuses. The mice have brains that are about 1 percent human. They have been developed to better understand neurological conditions, such as Parkinson’s, Alzheimer’s and Lou Gehrig’s diseases. Mice have also been developed with a nearly human immune system. They are used to test the response of the AIDS virus to new drugs.

_ Monkey-human chimeras

Researchers at St. Kitts Biomedical Foundation in the Caribbean have implanted immature human brain cells deep into the brains of vervet monkeys in hopes of developing a treatment for Parkinson’s disease. The human cells are injected into the dopamine-producing area of the monkeys’ brains to see whether the cells can grow and increase dopamine production.

MO PH END ORR

(J. Scott Orr writes for The Star-Ledger in Newark, N.J.)