Zhong Zhong and Hua Hua, born just two weeks apart, are the first two primates to be cloned using somatic cell nuclear transfer, the same method of cloning which produced the world-famous clone, Dolly the sheep almost twenty years ago. The two genetically identical monkeys, named after the Chinese word zhonghua, an adjective referring to Chinese people, are reported to be in good health.
A record of the achievement, recently published in Cell, states that somatic cell nuclear transfer has been achieved in a total of 23 mammalian species to date. Famously, sheep were the first species to be cloned in this way, but others animals have included cattle, sheep, dogs, and mice. Zhong Zhong and Hua Hua are macaques and the first primates to be cloned in this process. This also makes them the most genetically similar species to humans to be cloned like this.
Somatic cell nuclear transfer allows for multiple clones to be created from a single donor. The process does involve a surrogate mother carrying the clone to birth, however, hence Zhong Zhong and Hua Hua having different birthdays. According to National Geographic, the process involves inserting the nucleus from the donor DNA into an egg of another animal and chemically inducing the egg to develop as it would through natural fertilisation.
Out of 79 embryos, Zhong Zhong and Hua Hua are the only successes so far. According to CNN, Robin Lovell-Badge, an embryologist and head of the Division of Stem Cell Biology and Developmental Genetics at the Francis Crick Institute, finds the process to still be rather crude. “While they succeeded in obtaining cloned macaques, the numbers are too low to make many conclusions, except that it remains a very inefficient and hazardous procedure,”
Others in the scientific community are concerned about the ethics that this brings forward. Some have noted that being able to clone non-human primates is one step closer to the process of cloning humans, which would raise a huge number of ethical questions. Others are concerned about the treatment and quality of life of the animals produced in this method. It is an unfortunate truth that even the famed Dolly the sheep went through a number of health issues during her short life.
However, the team of Chinese scientists who made this breakthrough is adamant that the technology should not be used for human cloning. Rather, they see it as a way to advance medical science and research into human diseases. As the process is refined and better understood, it will hopefully also be possible to ensure better health and lifespan for cloned animals.
Zhong and Hua represent an incredibly complex issue in terms of science, medicine and the philosophical concepts of morality and the self. Regardless of what the future of cloning may be, they also represent an enormous achievement and a leap forward for scientific knowledge.