The monkey, which lived for 10 days before being euthanized, was made by combining stem cells from a cynomolgus monkey — also known as a crab-eating or long-tailed macaque, a primate used in biomedical research — with a genetically distinct embryo from the same monkey species. It’s the world’s first live birth of a primate chimera created with stem cells, the researchers said.
The researchers made the cells pluripotent — giving them the ability to organize into all the different cell types needed to create a live animal. Then they selected a subset of cells to inject into genetically distinct 4- to 5-day-old embryos from the same monkey species. The cells were also infused with a green fluorescent protein so the researchers would be able to determine which tissues had grown out of the stem cells.