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