A pair of cloned monkeys in China are reawakening questions… as well as fears… about whether humans will be next.
The primates… Zhong Zhong and Hua Hua (or just ZZ and HH for short)… like to jump around and play in their enclosure in a laboratory in Shanghai. They seem like any other healthy baby macaque monkey.
But they aren’t.
ZZ and HH were born from surrogate mothers using a process known as somatic cell nuclear transfer (SCNT) — the same process used to clone Dolly the sheep in 1996.
The Chinese researchers who oversaw the monkey cloning detailed their efforts in the journal Cell.
In SCNT procedures, the nucleus of a cell is taken from anywhere in an animal’s body and placed within an egg with its own DNA material removed. That egg is technically called an enucleated oocyte.
In Dolly’s case it was a mammary cell, hence the name Dolly as a nod to country singer Dolly Parton’s physical attributes.
The eggs are then stimulated to form embryos and placed into a surrogate womb where they are brought to pregnancy.
SCNT has been used to clone a wide range of animals, including cats, dogs, horses, rats, and others.
Although primates have been cloned before, most notably a rhesus macaque named Tetra born in 1999, ZZ and HH are the first primates cloned using SCNT.
“We’re excited — extremely excited,” Mu-Ming Poo, PhD, of the Chinese Academy of Sciences told NPR. “This is really, I think, a breakthrough for biomedicine”
He and his colleagues believe that genetically identical primates will allow for better research models for human brain diseases such as Alzheimer’s and Parkinson’s as well as subsequent therapies for them.
Headed to human cloning?
Cloned monkeys could also make for a better animal model because of how much more similar they are to humans than other mammals.
While that proposal has made for a tidy subheading, it’s largely been overshadowed by a bigger story.
The essential closeness between humans and primates is making some wonder whether this research is another stride toward human cloning.
“Monkey and related experiments are significant largely because they obviously bring us nearer to human cloning,” Michael Shapiro, JD, a law professor and expert on medical ethics at the University of Southern California, told Healthline.
However, that assertion comes with a giant asterisk because the nuances and ethics related to human cloning make the issue significantly more complicated.
With every passing year, the question is less “could we” clone a human than “should we.”
“In a way, it is one step closer, technically, but in a way, it’s not,” Marcy Darnovsky, PhD, executive director of the Center for Genetics and Society, a nonprofit advocacy group, told Healthline.
“Even though there are these two cute baby monkeys, [it] doesn’t really seem like it could count as a significant stepping stone toward human cloning,” she said.
Obstacles in cloning
According to Darnovsky, you need only examine the methodology of the experiment that eventually brought ZZ and HH to life to see the dangers of cloning:
Multiple surrogates, hundreds of eggs, numerous pregnancies — most of them failed.
In total, 63 surrogates were used, resulting in nearly 30 pregnancies and four births, of which ZZ and HH were the only ostensibly healthy offspring.
Two other baby monkeys resulting from the procedure died within two days of their birth.
“You couldn’t think about doing that kind of human experimentation,” said Darnovsky.
The debate surrounding cloning is incredibly dense, owing to moral, ethical, even ontological reasoning.
But, leaving the larger philosophical questions behind, there remain numerous health issues posed by human cloning for both the clones themselves and their surrogates.
Risks also abound for surrogates, owing simply to the labors of bringing a fetus to term, and, of course, the act of childbirth.
As for the potential clones themselves, Darnovsky is blunt:
“Mostly, cloned animals are not quite right. To try it in humans would be highly unethical,” she says.
“Not quite right” is a nice way of putting it.
Developmental anomalies, such as Large Offspring Syndrome, are known to occur in cloned animals, affecting quality of life and lifespan.
“There are of course issues related to animal rights and animal welfare that are different from human cloning issues, although there is some overlap,” said Shapiro.
The potential for suffering in “gravely impaired” clones does, according to Shapiro, represent a significant objection to human cloning.
Even if the birth of ZZ and HH did represent a move toward human cloning, is there really any desire to clone humans?
Poo appeared to respond to this question in his interview with NPR:
“Technically speaking one can clone human, but we're not going to do it. There's absolutely no plan to do anything on humans.”