Researchers at the Institute of Neuroscience at the Chinese Academy of Sciences in Shanghai, China have genetically modified monkeys to show symptoms of autism.
“Engineering of genes in animals (e.g., monkeys and rats) has been a way that researchers hope will help us be able to understand the disability [and] cause, and to test treatments,” Dr. Lynn Koegel, clinical director of the Koegel Autism Center at the University of California, Santa Barbara, said. “Autism is a very complex disorder that probably involves many genes.”
The use of animals in studying autism is not new. Previously, researchers relied on mice to study autism. The size of the rodents’ brains limited researchers from studying more complex aspects of autism. Macaque monkeys were specifically chosen in this new study for their similarity to human brains.
“The monkeys show very similar behavior to human autism patients, including repetitive behaviors, increased anxiety and most importantly, defects in social interactions,” Zilong Qiu, lead researcher at the Institute of Neuroscience, said. “We think it provides a very unique model.”
Scientists have recently found over 100 different types of genes related to autism — some of which are caused by spontaneous mutations. Researchers at the Chinese Academy of Sciences in Shanghai have chosen to focus on the gene methyl CpG binding protein 2 (MeCP2). This gene is most associated with a neurodevelopmental disorder called Rett syndrome, which leads to loss of a function. Many patients with Rett syndrome experience cognitive and motor impairment, seizures and growth failure.
Researchers introduced the MeCP2 gene into the genome of macaque monkeys by infecting egg cells with a virus carrying the gene. Embryos were then created using those eggs and transplanted into nine female monkeys, resulting in eight live births and two stillborns.
“MECP2 transgenic monkeys exhibited a higher frequency of repetitive circular locomotion and increased stress responses, as measured by the threat-related anxiety and defensive test,” according to the research report.
Additionally, researchers observed the gene and symptoms in the offspring of the transgenic monkeys.
Researchers hope that these monkeys will allow them to study autism more closely and develop future treatments of symptoms. Meanwhile, there have been negative responses to this research, including claims that the maltreatment of animals is unethical.
Even though there is a lot to learn from these monkeys, there are still limitations to this type of research.
“Because of the complexity, there may be limited applicability to humans,” Dr. Lynn Koegel said. “For example, animals do not use expressive verbal communication so we are not looking at the same core symptoms. Further, when we see humans with the same genetic mutations that were created with the animal models, they are often present with completely different symptoms, thereby making the animal models irrelevant to humans. In short, we’re a long way from any applicability to humans.”
It is estimated that over 3.5 million people in the United States live with autism. There is still a lot of research to be done on the different aspects of autism.
“People with autism have many strengths. They tend to be humble, intelligent and generally very nice people,” Dr. Robert Koegel, professor in the Department of Education and the Department of Counseling, Clinical and School Psychology at UCSB, said. “Most people focus on limitations, but people with autism also have many strengths that could benefit typically developing people.”
Special thanks to the Koegel Autism Center at the University of California, Santa Barbara. Undergraduate opportunities to work at the Koegel Autism Center are available.