A genetically cloned rhesus monkey has survived into adulthood for the first time, according to new research published yesterday. The healthy 3-year-old named Retro is just the third instance of a cloned primate to reach maturity after two 6-year-old long-tailed macaques born in 2018.
The achievement marks a rare success in a complex procedure—known as somatic cell nuclear transfer—which sees the vast majority of implanted primate embryos fail to reach birth. Researchers tweaked the process—the same used to produce Dolly the Sheep in 1996, the first cloned adult mammal—to prevent developmental defects associated with the cloned embryo's placenta. Some medical researchers believe cloned primates could prove more effective than commonly used mice in lab settings, while animal advocates argue the procedures cause undue stress to intelligent primates.
Thousands of animals—including carp, horses, wolves, and more—are cloned each year for agriculture and research, as well as for the preservation of personal pets.