Chinese researchers again triggered global scientific debates concerning the ethics of animal testing and the experimentation with human genome as they added a human gene tied to brain development to monkeys’ DNA to study brain development. Researchers from the Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology and partners organizations added a human gene tied to our species’ brain development to 11 monkey embryos to study its impact on brain growth which thereafter triggered global debates on animal ethics. One of the researchers even became critical of the work himself.
The researchers note in the abstract that brain size and cognitive skills are dramatically changed in humans during evolution and yet, the genetic mechanisms underlying these human-specific changes remain elusive. The scientists generated 11 transgenic rhesus monkeys (8 first-generation and 3 second-generation) carrying human copies of MCH1, an important gene for brain development and brain evolution. Brain image and tissue section analyses indicated an altered pattern of neural cell differentiation, resulting in a delayed neuronal maturation and neural fiber myelination of the transgenic monkeys, similar to the known evolutionary change of developmental delay (neoteny)in humans.
Further, brain transcriptome and tissue section analyses of major developmental stages shows a marked human-like expression delay of neuron-differentiation and synaptic signaling genes, providing a molecular explanation to the observed brain developmental delay of the transgenic monkeys.
Importantly, the transgenic monkeys exhibited better short-term memory and shorter reaction time compared to the wild type controls in the delayed matching to sample task. The presented data represents the first attempt to experimentally interrogate the genetic basis of human brain origin using a transgenic monkey model, and it values the use of nonhuman primates in understanding human unique traits.
TrialSite News understands in the pursuit of cures and treatment to deadly and debilitating diseases, society must depend to some extent on preclinical animal research. There are general guidelines and ethics policies, not to mention institution-specific policies. However, primates fall into a particularly special category. We should not experiment with them unless there is a valid and compelling reason—e.g. in the pursuit of a cure for cancer or a debilitating childhood disease.
In this case, it appears nothing more than basic science academic investigation. We don’t think it appropriate to sacrifice primates in all cases and this very well could be one of them.
Bing Su, Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology
Weizhi Ji, Yunnan Key Laboratory of Primate Biomedical Research, Institute of Primate Translational Medicine, Kunming University of Science and Technology