Human-pig chimera (courtesy National Geographic)

Human-pig chimera (courtesy National Geographic)

The government of Japan is revising guidelines on the creation of chimeric human-animal embryos to permit organ harvesting and other experiments.

The Ministry of Education, Culture, Sports, Science and Technology is expected to drop a current ban on the procedures, which involve creating embryos including both human and animal cells and injecting them into the uteruses of pigs and other lab animals.

Currently, Japan permits only the injection of cells, such as human induced pluripotent stem cells (iPS cells), into fertilized animal eggs. A panel of experts approved the transplantation of the resulting embryos into the uteruses of animals and the resulting offspring. Animals such as pigs are being considered for the procedure because the sizes of their organs are close to those of humans.

Creating human organs in animals, they say, could help address the shortage of organs for transplants. Also, it is hoped that creating animals that can develop human diseases could aid research into the development of new medical treatments for humans.

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The panel also approved research to produce human brain cells, eggs and sperm, but it maintained a ban on the creation of animals with high cognitive abilities similar to humans.

The change is policy could take effect as early as April.

Researchers in other countries, including the United States, have been trying to grow human pancreases and other organs in pigs to use for transplantation.

The draft bans inseminating the reproductive cells of chimeras to produce offspring because such cells could contain human DNA.



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