Science Friday

This week, a research team in China reported that it had successfully cloned a rhesus monkey, which has lived normally for over two years and reached maturity. It marks the first time that a rhesus monkey has been successfully cloned. Rhesus monkeys are used widely in medical research, making the advance potentially useful for medical trials.Cloning of primates in general has been difficult. Six years ago researchers cloned long-tailed macaques using the technique originally used for Dolly the cloned sheep. But an attempt to use that approach to clone a rhesus was unsuccessful, producing an animal that died after 12 hours. In the new work, the research team identified flaws in placental cells of previous cloned embryos. To address those flaws, they replaced the outer trophoblast cells from a developing cloned embryo with ones from an embryo created through an in-vitro fertilization technique—essentially providing cells that would develop into a normal placenta for the cloned embryo.Tim Revell of New Scientist