Researchers from the Chinese Academy of Sciences’ Institute of Neuroscience in Shanghai have been the first to clone genetically-altered primates. Five infant macaques share the exact same genes, derived from a fibroblast taken from the skin of a donor monkey. This technique could theoretically produce an unlimited number of replicas and provide clear benefits for medical testing.
Almost exactly one year ago, the first non-modified primates were cloned through a somatic cell nucleus transfer technique. Now, scientists have used the same technique to produce five clones of another monkey. It was genetically altered (with CRISPR/Cas9 gene-editing technology) to display a disorder with an array of psychological side effects. Their research was published in two papers, in the journal National Science Review.
The altered gene BMAL1 normally produces a regulatory protein that plays a role in managing certain biological rhythms in mammals. Consequently, animals could not produce the protein causing them to exhibit symptoms of circadian disorders, such as reduced sleep and increased movement at night. Furthermore, they showed signs of anxiety and depression, along with schizophrenia-like behaviors.
“Disorder of circadian rhythm could lead to many human diseases, including sleep disorders, diabetic mellitus, cancer, and neurodegenerative diseases,” said neuroscientist Hung-Chun Chang. “Our BMAL1 knock-out monkeys thus could be used to study the disease pathogenesis as well as therapeutic treatments.”
Today, using genetically altered animals to study illness is an everyday practice. According to the researchers, creating clones of transgenic models could help limit variables in future experiments. Because the cloned animals are identical, it is easier to notice subtle effects that otherwise could be missed. However, some people believe the benefits are not as near sufficient to justify this kind of treatment toward animals.
During the cloning process, the team transferred 325 embryos into 65 surrogate mothers. This resulted in 16 pregnancies and only five live births, leaving many ethical questions open. Can distress of the animal survivors justify the cause of treating human psychological disorders? Especially since animal models do not necessarily translate into human biology as easily as we might expect.
Some researchers believe that genetic engineering could actually be a solution to reduce the number of animals used for experiments, not increase them.
“This line of research will help to reduce the amount of macaque monkeys currently used in biomedical research around the world,” said neuroscientist Mu-ming Poo. “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.”
Deborah Cao from Griffith University in Australia is an expert on animal welfare, ethics, and law. She strongly disagrees with this kind of politics. According to her, international guidelines for this kind of research are necessary.
“The best way to reduce the number of monkeys used in such experiments is to stop such animal experiments,” Cao said for Newsweek. “Instead of developing nonhuman primate disease models for humans, they should develop human disease models for humans.”
At the moment, China is a controversial testing ground for the ethical limits of genetic engineering technology. Time will tell whether this practice will become accepted as a common way to supply transgenic animal models.
Learn more about the research in the video below:
By Andreja Gregoric, MSc