Monday, September 28, 2020
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In Breakthrough, Scientists Clone Monkeys

Source: Chinese Academy of Sciences
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For the first time, scientists in Shanghai have successfully cloned a primate, creating two identical female crab-eating macaque monkeys named Zhong Zhong and Hua Hua. The scientists performed the cloning in December 2017, and published their findings in the journal Cell in January 2018. The scientists used somatic cell nuclear transfer (SCNT) to clone the monkeys.

Because the successful cloning of these monkeys may lead to the cloning of humans, ethical questions regarding human cloning have been raised by critics. Other people are optimistic, saying that the cloning will provide researchers with knowledge about human diseases.

How Somatic Cell Nuclear Transfer Works


Steps of SCNT

SCNT involves two cells, an immature egg cell, known as an oocyte, and a somatic or body cell, containing the DNA that will be cloned. In the cloning of the monkeys, the scientists used fetal fibroblasts (cells that synthesize the structural framework of tissues).

Using a microscope, UV light, and a glass needle, the oocyte’s DNA-containing nucleus is removed, a process is called enucleation. Scientists attach a florescent tag on the DNA before enucleation to make sure all the DNA has been removed.

Both the somatic cell and the enucleated oocyte are put into a serum solution. The somatic cell’s nucleus is extracted with a pipette and is placed into the enucleated oocyte. The oocyte “reprograms” the nucleus to ensure that the nucleus functions properly. Then, the combined cell is electrically shocked a few times to make sure that the nucleus and oocyte fuse completely. The resulting cell then divides several times. In reproductive cloning, the group of cells are inserted into the surrogate mother, and in a successful scenario, the surrogate mother gives birth to the cloned organism that arises from the cells. In therapeutic cloning, the group of cells are used to replace cells of certain tissues. For example, in a patient with diabetes, the damaged insulin-secreting cells could be replaced with cells generated from therapeutic cloning.

According to their article in the Cell journal, the scientists who cloned the monkey modified the SCNT process, “including polarized-light imaging for the removal of [the nucleus] from the oocyte, incubation of the nuclear donor cell with viral envelope isolated from the Hemagglutinin Virus of Japan, and facilitation of donor cell insertion into the perivitelline space with laser lesion of zona pellucida.” These modifications were necessary to ensure that the cloning was successful.


When the scientists tried to use adult cumulus cells (cells that naturally surround, protect, and support the oocyte) to provide the nucleus in SCNT, 181 embryos were transferred to 42 surrogate mothers, resulting in 22 pregnancies. 2 short-lived monkeys were born. However, when the scientists used fetal fibroblasts to provide the nucleus, 79 embryos were transferred to 21 surrogate mothers, resulting in 6 pregnancies. Ultimately, 2 healthy monkeys were born, Zhong Zhong and Hua Hua. The scientists report that the two monkeys are still healthy and display normal mental and physical development.


The cloning of the monkeys has been praised by some and condemned by others. In their article in Cell, the scientists who cloned the monkeys say that continuous cloning of this species of monkeys could be “relevant for developing monkey models for human diseases with defined genetic defects [and] could be used for studying disease mechanisms and testing potential therapeutic treatments. Basic studies on the genetic basis of primate-specific traits will find genetically uniform clones of non-human primates a useful laboratory animal model.”

According to CNN, Muming Poo, one of the scientists, says that the Chinese government plans to increase the size of the cloning project, predicting that there will be more than 20 facilities cloning monkeys in the future. Poo shrugs off the concern of human reproductive cloning, claiming that he and his team have no intentions of pursuing human cloning. Instead, the clones will be used by researchers to study genetic diseases such as autism, Alzheimer’s, and Parkinson’s. According to James Bourne, an associate professor and National Health and Medical Research Council senior fellow of the Australian Regenerative Medical Institute at Monash University, the cloning “could be an important tool in medical research for understanding disease in a species genetically comparable to humans.”

On the other hand, many people denounce the cloning of the monkeys. Some critics, such as PETA, say that the cloning of the monkeys was animal abuse; according to PETA Senior Vice President Kathy Guillermo, “cloning has a failure rate of at least 90 percent [and] these monkeys represent misery and death on an enormous scale.” Other critics of the cloning charge that the cloning of monkeys is one step closer to human cloning, who are closely related to monkeys. Opponents of this viewpoint say that the conclusion that human reproductive cloning will happen is not logically justified because future regulations will likely prohibit human reproductive cloning from occurring.

According to the Stanford Encyclopedia of Philosophy, the main ethical objections to human reproductive cloning are that

  1. SCNT on humans may impose genetic risks on the clone, and the clone cannot consent to accepting the risks imposed on him/herself in the process of cloning.
  2. Cloning may threaten the individuality and autonomy of the clone. This may reduce the clone’s wellbeing and the human rights of the clone.
  3. Cloning may be performed with dubious motives, such as a couple wanting an extraordinarily beautiful child, or a political leader wanting an army of clones
  4. Clones may be looked down upon and discriminated in society
  5. Human reproductive cloning may be taken advantage of by the government to implement eugenics, where humans are selectively bred to produce favorable traits (for example, Hitler effectuated eugenics by sterilizing, segregating, and euthanizing specific groups of people, including Jews). The government may clone someone with a certain set of traits, and force the clones to reproduce and pass on those traits.

The move to increase the size of the cloning project delivers a clear message: the clonings of more species will occur with more countries and organizations, . Armed with the experience and knowledge of these future clonings, countries or organizations will easily be able to clone humans, if they wanted to. However, whether cloning happens because of a dictator wanting to build an intelligent super-army, or a corporation wanting to produce “perfect” children for wealthy couples, someone will almost certainly have the motive to clone humans, regardless of the legality of human cloning. If human cloning happens, at best, the clones may cause a rift in society between clones and other humans, and at worst, clones may be used as a tool of the elites to achieve sinister political goals. On the other hand, it is irrefutable that the cloning of the monkeys will lead to advancements in understandings in human health and science. However, cloning monkeys is definitely not the most money-efficient way to advance understandings in health and science. The cloning of monkeys has been inefficient, and therefore expensive; the expansion of the cloning project will cost hundreds of millions of dollars. Thus, the monkey cloning project should not be expanded—the project is both expensive and ethically unsound.



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