Zhong Zhong (Chinese: 中中; pinyin: Zhōng Zhōng, born 27 November 2017) and Hua Hua (Chinese: 华华; pinyin: Huá Huá, born 5 December 2017) are a pair of identical crab-eating macaques (also referred to as cynomolgus monkeys) that were created through somatic cell nuclear transfer (SCNT), the same cloning technique that produced Dolly the sheep in 1996.
[1][2][3][4][5] The primates were born from two independent surrogate pregnancies at the Institute of Neuroscience of the Chinese Academy of Sciences in Shanghai.
[3] Tetra (born October 1999), a female rhesus macaque, was created by a team led by Gerald Schatten of the Oregon National Primate Research Center using a different technique, called "embryo splitting".
This crucial reprogramming step allowed the researchers to overcome the main obstacle that had precluded the successful cloning of primates until now.
[1] According to Mu-ming Poo, the principal significance of this event is that it could be used to create genetically identical monkeys for use in animal experiments.