Scientists have produced the world’s first chimeric monkeys, developed from stem cells harvested from separate embryos. They contain genetic material from as many as six genomes. The infant rhesus monkeys are totally healthy and could hold great promise for future stem cell research in primates, researchers say. They also carry an interesting and controversial message for future stem cell research: Those cultured stem cell lines in labs throughout this country, such a crucial scientific tool and such a cultural flashpoint, may not be as potent as the ones inside embryos.
The monkeys, named Roku, Hex and Chimero, were born at the Oregon National Primate Research Center at Oregon Health & Science University. They’re the result of mashups made from separate rhesus monkey embryos. Researchers took very early stem cells, called totipotent stem cells, from separate developing embryos and basically glued them together, implanting the mixed embryos into surrogate mother monkeys. The cells — from totally different sources — didn’t fuse, but worked together in harmony, forming fully fledged, normal, healthy animals. Watch them do baby monkey things in the video below.The key here was the scientists’ use of totipotent cells, so named for their ability to differentiate into the totality of possible cells in an animal. A totipotent cell can give rise to a whole animal. Pluripotent stem cells, the type most frequently used in stem cell research, can differentiate into any cell in the body, but can’t become a whole animal, and can’t make other embryonic tissues like a placenta. Totipotent stem cells are only derived from the very earliest stages of a zygote, mere days after fertilization. In humans, totipotent cells differentiate into pluripotent cells after four days.