Science in an Ethical Vacuum: Cloning Monkeys for Research

The Physicians Committee

Good Science

Science in an Ethical Vacuum: Cloning Monkeys for Research

  February 23, 2018  


In February 2018, science fiction became science fact, as scientists in Shanghai reported the successful cloning of cynomolgus monkeys (long-tailed macaques) using a process called somatic cell nuclear transfer (SCNT). This is the same process used in 1996 to clone Dolly the sheep, and it was subsequently used to produce live births in more than 20 other species.

But SCNT uniformly failed in primates until the Shanghai group discovered how to promote the growth of the created embryo in a surrogate mother macaque. Although nearly all the implanted embryos did not survive, two live births resulted—genetically identical sisters Zhong Zhong and Hua Hua.

SCNT operates by obtaining a donor oocyte (egg cell), then removing the nucleus and inserting a cultured fetal fibroblast (connective tissue cell) from an aborted fetus. Techniques developed by the Shanghai researchers promote the development of the created embryo after transfer to a surrogate mother (Figure).

Cloning of macaque monkeys by  somatic cell nuclear transfer.

Source: Liu, et al. Cloning of macaque monkeys by somatic cell nuclear transfer. Cell 2018;172:1-7

The purpose of this research is to create populations of genetically identical monkeys to facilitate research into human diseases, and particularly neurological disorders such as dementia and Parkinson disease that have escaped elucidation and treatments based on animal research. The presumption is that by eliminating genetic variation as a complicating factor, fewer monkeys can be used while obtaining more reliable information from (for example) monkey brain research.

Concerns and objections to this research are based on the claimed usefulness of the cloned monkeys for human-relevant science and on several ethical issues, raised even by the researchers themselves. The cloning of genetically identical monkeys does not address the fundamental reasons that nonhuman animal research is unreliable for human applications. These reasons include extensive and immutable genetic differences between humans and nonhuman primates (here, here, and here), including very different brain genetics (here, here, and here).

Since human monozygotic (identical) twins differ in gene expression, disease risks, and responses to treatments (here and here), even for brain disorders, claims that the cloned monkeys can translate to human benefit are unscientific.

Regarding the ethical concerns, where do we start? The SCNT process begins by aborting a fetus from a mother impregnated for that purpose. Another monkey has an egg cell removed from her ovary. Then after the egg cell and fetal fibroblast are fused to create the embryo, it is transplanted into a third monkey (the surrogate mother). If the embryo produces a live birth, the newborn is taken from the mother and maintained in a captive environment, only to be used and killed in cruel and futile experiments.

Finally, this achievement by Chinese scientists moves us one huge step closer to the possibility of cloning humans, a process these researchers state they will not pursue. But there is a reliable dogma in medical science: If it can be done, someone will do it. Only legislation and science ethics prevent this, and does anyone want to rely on those shaky deterrents? 

Legendary World War II general Omar Bradley stated regarding the advent of the atomic bomb: "The world has achieved brilliance without wisdom, power without conscience." As China awaits the birth of as many as six more cloned monkeys, here we are again.

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