Researchers have achieved a new kind of chimeric first, producing sheep-human hybrid embryos that could one day represent the future of organ donation – by using body parts grown inside unnatural, engineered animals. With that end goal in mind, scientists have created the first interspecies sheep-human chimera, introducing human stem cells into sheep embryos, resulting in a hybrid creature that’s more than 99 percent sheep – but also a tiny, little bit like you and me.
Admittedly, the human portion of the embryos created in the experiment – before they were destroyed after 28 days – is exceedingly small, but the fact it exists at all is what generates considerable controversy in this field of research. “The contribution of human cells so far is very small. It’s nothing like a pig with a human face or human brain,” stem cell biologist Hiro Nakauchi from Stanford University told media at a presentation of the research this week in Austin, Texas, explaining that, by cell count, only about one in 10,000 cells (or less) in the sheep embryos are human. READ MORE