Pinpointing the root of autism development has been a challenge for researchers, as multiple genes and environmental factors all play a role. Furthermore, the majority of brain research is conducted in rodents, who do not mimic the complexity of brain disorders found in humans. Recently, a team of researchers in China have launched a ground-breaking study to observe autism behaviors in monkeys.
The team introduced a human gene called MECP2 in the genome of macaques (a type of monkey), causing them to display behavior symptoms similar to those found in children with MeCP2 duplication syndrome, which produces autistic-like behaviors. These behaviors include limited social interaction and repetitive motions. Furthermore, the research team found that the monkeys were able to pass the gene and symptoms along to their offspring.
Although this study offers a new insight for researchers, it is still debatable if it is effective to use primates to study human brain disorders. Many children with the duplication syndrome meet the formal criteria for autism diagnosis, but also tend to have symptoms that are atypical of autism.
Although researchers are debating this study worldwide, the team of scientists who produced the monkeys are more optimistic. Zilong Qiu, neuroscientist at the Chinese Academy of Sciences in Beijing and co-author of the study states, “[they] are the first primate models of autism. I’m thrilled by the possibility that we may be able to reverse the genetic causes in the transgenic autism monkey model.”
MeCP2 duplication syndrome occurs in humans when there are extra copies of those specific genes. To replicate the syndrome, the research team genetically modified monkey embryos by introducing the gene to the monkey’s DNA. Next, they implanted over 50 embryos into 18 monkeys, with eight baby monkeys being born as a result. The monkeys each displayed symptoms common to children with the duplication syndrome, including anxiety and deficits in social interactions with the other monkeys.
Qiu and his team are now using brain imaging technology to identify the brain circuits that play a role in the monkeys’ autistic behaviors. If they can properly identify the areas affected, they may be able to lead developments that target these areas for treatment. Alysson Muotri, human brain development researcher at the University of California-San Diego states, “[The monkey models] aren’t perfect, but they could be better than mice designed to replicate the syndrome.” She continues, “At least the [monkeys] could mimic autism-like behaviors.”