When scientists start mapping of the human genome, they discovered thousands of genes that have weakened us against diseases, including certain types of cancer. The discovery of the weaker genes led scientists to ask this question: “What if we can cut off these genes and put other genes instead?”
The CRISPR method, introduced in 2013, was inspired by the defense mechanisms that bacteria use to protect themselves from viruses. Basically, the bacterium, by means of a guide RNA, adapts itself to a part of the virus DNA and cut off a piece of DNA with the enzyme cas9. By using this method, researchers can find and replace a DNA sequence in any organism.
The method, tested in mice and monkeys, promises many genetic disease treatments. Things like power, speed, and intelligence can be changed in mice. DNA-injected mice that encode a fat-burning protein can move twice faster than normal mice.
Although this method is quite advanced, it’s quite possible to make things worse with the fact that even a simple concept such as length, can be affected by more than 180 genes and also we can’t fully understand the communication between the genes.
In addition the outcome of the method is unpredictable, and having only 20% -30% success rate in monkeys indicates that the method isn’t healthy enough for human experiments for now.
In 2015, however, an important step was taken about genetically manipulating in human by replacing the genes that cause blood diseases called β-thalassaemia in embryos for the first time in China. And in 2016, England took big steps towards allowing “genetically modified babies”.
Although we can’t yet develop our own traits, CRISPR gene therapy can help to prevent genetic diseases and diseases caused by mutations such as Huntington and Tay-Sachs.