When South Park‘s parody of Al Gore warned the world of Manbearpig in 2006, show creators Trey Parker and Matt Stone probably didn’t imagine that within 10-years genetic engineers would actually be mixing porcine (pig) and human genomes. Despite a moratorium by the National Institutes of Health (NIH), through which the government agency essentially decided not to fund research on human-animal chimeric genome editing, a group from UC-Davis is moving forward introducing human stem cells into pig embryos. The BBC reported these experiments after gathering material for the program “Medicines Big Breakthrough: Editing Your Genes” for Panorama.
The UC-Davis team introduced stem cells from humans into the embryos of pigs. The goal of such experiments is to have the pigs develop human organs that could be implanted into humans without the transplant rejection often associated with animal organ donations, or “xenografts”.
The science team first genetically modified the pig embryo such that it would not develop a pancreas; then they injected human embryonic stem cells. Their hypothesis is that the human cells will be called upon to fill the void and begin to develop a functional and integrated pancreas. Sows were implanted with the chimeric pig embryos, and the team will let the embryos develop for 28 days, or almost 25% of a porcine pregnancy, by which time the pancreas should begin developing. The research team will then analyze the progression of embryonic pancreatic development.
The BBC’s own press release on Monday discusses in greater depth the science of these experiments, the great impact this could have on organ transplantation, the ethical treatment of lab animals for organ generation and harvesting, and the moral conundrums of beginning to make animals with human features. For now though, the threat of Manbearpig is still distant.