This year, the first primates, cloned using core transfer technology, became titles all over the world this year. Now, Chinese researchers have pushed the shell even further – breaking a regulatory gene at the macaques before cloning them.
According to the researchers, cloning of genetically modified primates has clear benefits for medical tests. But as a result of the controversy over editing genes on humans, progress in this controversial area may outpace ethics.
Following the new experiment, five macaques born at the Institute of Neurology at the Chinese Academy of Sciences all share the same genes derived from fibroblast derived from donor monkey skin.
More importantly, they all carry a copy of a specific gene version of BMAL1
. This gene usually produces a regulatory protein that plays a role in management of some biological rhythms in mammals. But in the altered version, this protein is not produced, which causes animals to exhibit symptoms of circulatory disturbances such as reduced sleep and greater movement at night
They also show signs of anxiety and depression along with schizophrenic behavior.
"Circadian rhythm disorder can cause many human diseases, including sleep disorders, diabetes mellitus, cancer and neurodegenerative diseases," says neuro-physiologist Hoon-Chun Chang.
"Our BMAL1 monkeys can be used to study the pathogenesis of the disease as well as therapeutic treatment."
Using genetically modified animals to study the disease is almost certainly in today's medical research. Scientists regularly change genes with mice, flies and fish to investigate their physiological effects. Meanwhile, creating clones of transgenic patterns helps to limit experimental variables. Each animal is identical to the latter, which makes it easier to spot the subtle effects that might otherwise be missed.
Cloning of transgenic primates has not been possible until recently, largely due to the way their genes block epigenetically when fertilized cells occur.
Last year, the Chinese Institute of Neuroscience reported the successful reproduction of two long-tailed macaques using somatic cell kernel transfer, the same process produced by world-renowned sheep Dolly in 1995.
For some, however, these scientific successes come at an unacceptable price.
"The monkey after the monkey was made to live in harsh conditions and then dies in a few days," British journalist Hours Newkird-Burdon writes in The Independent
"PR people do not say the names of these babies. "
This time, the team transferred 325 cloned embryos to 65 surrogate mothers, resulting in 16 pregnancies
Whether the loss of life and the potential for suffering and distress in surviving animals is balanced by the possibility of treating debilitating psychological human disorder is a complex issue of ethics. Animal models do not necessarily turn into human biology as easy as we could expect, which raises fears that the results may not cost the potential harm.
However, researchers are opposed to the fact that genetic engineering can actually be a solution to a bigger problem. This line of research will help reduce the amount of macaque monkeys currently used in biomedical research around the world, "said Muonging Poo neuroscientist, who contributed to both the editing of the original macaque and its cloning, the interference of the genetic background , a much smaller number of cloned monkeys carrying disease phenotypes may be sufficient for preclinical tests of the efficacy of the therapeutic agents. "
She agrees. Deborah Kao of Griffith University in Australia is an expert on animal welfare, ethics and law. She points out the lack of international guidelines for this kind of research. "The best way to reduce the number of monkeys used in such experiments is to stop such experiments with animals," said Cao Newsweek reporter Hannah Osborne. for humans, they need to develop human disease patterns for humans. "
China is currently a controversial test of the ethical limits of genetic engineering technology. At the end of last year, Chinese scientist Han Jiankui announced the first genetically modified babies in the world after editing CRISPR.
Since then, he has been accused of forgery of ethical approvals, and then there are rumors that he was taken over by the authorities. Time will show if these five cloned macaques predict a new era in transgenic animal models or represent an ethical line, few will tend to return again soon
This study is published in National Science Review here and here.