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发帖数: 12553 | 1 Chinese Scientists Cloned Gene-Edited Monkeys With Horrifying Results
Kristin Houser in Hard Science
A team of Chinese scientists just unveiled five cloned monkeys produced from
the cells of a monkey whose genes they edited with CRISPR-Cas9.
Cloned Again
Almost exactly one year ago, the world met Hua Hua and Zhong Zhong, the
first primates cloned through a technique that could theoretically produce
an unlimited number of replicas.
Now, a team of Chinese scientists has used the same technique to produce
five clones of another monkey, one genetically altered to have a disorder
with an array of traumatic psychological side effects — and the research is
a horrifying ethical minefield.
Off-Rhythm
The technique used to clone the monkeys is called somatic cell nuclear
transfer, and it involves replacing the nucleus of a donor egg with one
removed from the cell of another animal.
With Hua Hua and Zhong Zhong, scientists retrieved their donor nucleus from
the cells of fetal macaques.
This time, though, researchers from the Chinese Academy of Sciences used the
nucleus of cells from a genetically altered monkey. Specifically, they used
CRISPR-Cas9 to alter the animal’s BMAL1 gene, which helps manage certain
circadian rhythms in some mammals, while it was still an embryo.
According to the researchers’ two papers, both published in the journal
National Science Review, the procedure worked.
The five newborn monkeys exhibited a “wide-range of circadian disorder
phenotypes,” including reduced sleep, increased movement at night,
schizophrenia-like behaviors, and signs of anxiety and depression — all of
which are on display in a disturbing video released alongside the research.
Of Monkeys and Men
While the idea of purposely subjecting animals to the psychological stresses
described above is troubling, the researchers believe the potential
benefits to humanity are worth it.
“Disorder of circadian rhythm could lead to many human diseases, including
sleep disorders, diabetic mellitus, cancer, and neurodegenerative diseases,
” researcher Hung-Chun Chang said in a press release. “Our BMAL1-knock out
monkeys thus could be used to study the disease pathogenesis as well as
therapeutic treatments.”
There’s also the possibility that cloning genetically altered animals could
actually reduce the number needed for research.
“Without the interference of genetic background, a much smaller number of
cloned monkeys carrying disease phenotypes may be sufficient for pre-
clinical tests of the efficacy of therapeutics,” researcher Mu-ming Poo
said in the press release.
Sleepless Nights
At the same time, the research raises a host of ethical issues.
For one thing, there’s the large number of unsuccessful attempts that
preceded the births of these five monkeys to consider — 65 surrogate
mothers underwent embryo implantations, resulting in 16 pregnancies but only
five births.
Then there’s the lingering question of whether any insights gleaned from
the research would even translate to humans — many animals studies don’t.
“If I were on an ethics review committee, I would be very hesitant to
approve [this research] because of the incredible amount of harm to the
animals,” bioethicist Carolyn Neuhaus told Gizmodo. “I would expect the
scientists who are proposing this research to have very good responses to
very hard questions about their methods and the expected benefits of their
research.”
READ MORE: Chinese Scientists Have Cloned a Genetically Altered Primate for
the First Time [Science Alert] |
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