New Breakthroughs in Autism May Come From Monkeys

Scientists have now begun to genetically engineer monkeys in order to study behaviors similar to autism. By manipulating the MECP2 gene, most commonly found in boys that have a duplicate pair of the gene, scientists hope to study potential therapies on the animals that could one day be of help to human subjects. This genetic disorder is known to cause Rett syndrome, a severe type of developmental autism disorder. 

 

While most studies on autism in the past have tended to use mice, the complex nature of autism is unable to be thoroughly studied on such a simple animal. Jonathan Sebat, chief of the Beyster Center of Psychiatric Genomics at the University of California in San Diego mentioned in the New York Times article, "Mice are not in the same league when you’re talking about doing models of social cognition and interaction. They're not even close." Jonathan was not involved in the monkey research. 

I agree with  Dr. Jonathan Sebat that it makes sense that answers from studying such a complex disorder like autism will not come easily from such a simple organism like mice. Autism has a lot to do with the human brain and the social interaction that goes along with it. Using a fellow primate to test seems more logical. That being said, using monkeys instead of rodents comes with its financial and ethical costs. Monkeys are much more expensive to test and genetically manipulate, and "some animal rights advocates here are more troubled by research on mice than on rodents." 

 

In conclusion, it does not look like mice will be losing their jobs as lab rats anytime soon, given that the cost of genetically engineering monkeys is still so expensive. Dr. Sebat also adds that although monkeys with the MECP2 mutation is a logical place to start, other mutations in monkeys may end up being better to test medications. Although she is also not involved in the study, Dr. Sarika Peters, a clinical researcher of autism at Vanderbilt University School of medicine, claims to be "cautiously optimistic about the study," believing that, "monkeys may be the animal model with the most relevance to human autism."

long tailed macaque: one of the species of monkeys used in the study

 

 

 

 

 

Transgenic Monkeys as Disease Models

     Anthony Chan, a geneticist at Emory University in Atlanta, GA, spent two years creating the first monkeys to be genetically engineered with human mutations.  The primates were given the mutations for Huntington's disease.  Three of the five monkeys developed severe symptoms of the disease more quickly than anticipated and were put down within a month of birth.  The method in which viruses were used to introduce the gene posed an issue; where the virus inserted extra copies of the relevant gene randomly.  Which caused the severe development of the disease.  This issue thus presented its limitations when creating new animal disease models.

     The use of transgenic monkeys as animal disease models will more accurately mimic the disease symptoms and reaction to treatments that is present in humans compared to mice models.  Neuroscientists have waited for the ability to use transgenic monkeys in research for disorders such as autism, schizophrenia, and Alzheimer’s disease.  Disorders such as these cannot be replicated accurately in mice because they lack complex cognitive and social abilities.  Many neuro drugs that have shown positive results actually ended up failing when tested on humans. 

       Precision genome-editing techniques that may solve the problems presented by the viral technique are now being worked on. These techniques will work by using enzymes and RNA instead of viruses. A disadvantage with the use of monkeys instead of mice as a model is the lengthy time it takes for maturity.  “Custom” monkeys have become a possibility due to efficient gene-editing techniques that support a method in which embryos are manipulated one at a time however.  One method used is called CRISPR. A customizable RNA fragment is used to guide a DNA-cutting enzyme to the right spot.  Feng Zhang, a synthetic biologist at the Massachusetts Institute of Technology (MIT) in Cambridge, showed that CRISPR could be used to make precise mutations in multiple genes in mouse embryos. This method could make it possible to use monkeys as models of human brain disorders that involve more than one gene.  CRISPR is now being tested on fertilized monkey eggs.

The use of monkeys is a great model since observations regarding symptoms and reaction to treatment would be more accurate when compared to mice.  The use of mice as a model for many disorders and diseases is useless in many cases.  A problem that will/is going to be met of course would be ethical.  However, the use of mice as a model organism is just as unethical as using a monkey. They are both animals, but the use of monkeys would be more useful.  The testing on mice is especially unethical when there really is no purpose due to the lack of results that would be obtained at the end.  I do no believe in the harm of animals but the use of transgenic monkeys may be very beneficial in research of serious neurological disorders!

http://en.wikipedia.org/wiki/Transgenesis

http://www.scientificamerican.com/article.cfm?id=precision-gene-editing-paves-way-for-transgenic-monkeys

Mutations Effects on Cilium

Two teams of researchers from the Baylor College of Medicine have found a way to make a three-dimensional map that can be used to better understand how the structure of the cilium can be disrupted by genetic mutations. The cilium is a type of photoreceptor in the eye and it helps transports proteins during the light-sensing process. Cilia are a very important component for most mammalian cells. "They play a central role in cellular operations, and when they are defective because of genetic mutations, people can go blind, have cognitive defects, develop kidney disease, grow too many fingers or toes or become obese." The three-dimensional design that these researchers were able to develop was discovered by studying three mice known to have ciliopathies (a disease in the cilium). Researchers used cyro-electron tomography to compare rod structures in the outer structure in healthy mice to the ones that had these ciliopathies. The three-dimensional structure that they were able to create showed that there are vesicles tethered to membrane filaments. Further studies on a specific disease known as Bardet Biedl Syndrome showed that, "...aberrant trafficking of proteins is responsible for photoreceptor degeneration." This degeneration is what could be responsible for many cilial diseases.



Overall, I found this information to be very interesting. It was good to know that many diseases in people can be caused due to a genetic mutation in such a small body part. I would hope that this new found information would be able to help scientists develop ways to better identify those individuals that may have these kinds of mutations and ultimately be able to develop treatments for these diseases as well.