Jordan Healey, Science and Technology editor, looks into a new groundbreaking form of gene editing and the many potential applications it could hold for the future.
Recently there has been a lot of hype about a remarkable new form of technology called CRISPR. This technology could allow us to manipulate DNA in order to ‘fix’ various genetic defects and diseases – it even has potential to genetically engineer humans in the near future! Needless to say, this is a topic that has many ethical concerns and will need to undergo a series of stringent tests before being made publically available. However, Jennifer Doudna, co-founder of the CRISPR Cas-9 technology, has predicted that this scary new method of gene editing could be ready to launch within the next ten years. But what exactly is CRISPR?
CRISPR is an adaptive immune system that has evolved in certain types of bacteria (it was discovered in E-coli) and can destroy viral DNA as it attacks the bacteria cells. It does this by storing the viruses genetic information within the bacteria’s RNA (the molecule responsible for DNA coding and decoding). This RNA then seeks out the bacteria’s DNA that has been attacked by the virus and a protein called cas-9 ‘cuts’ this faulty strand of DNA where there is a match. This is important because this relationship between the RNA and the protein can be applied to human DNA meaning that it can act in such a way that we can edit our own genetic code. This method is extremely precise, cost effective and quick. Furthermore, it has already been proven to work in various different animals. It also has various applications in agriculture as well as the prevention of malaria, which killed more than 400,000 people in 2015 alone.
The Bill and Melinda Gates Foundation has already donated US$75 million into a project called Target Malaria which is currently researching the use of CRISPR technology to initiate a gene drive within the mosquito population. Gene drives involve human intervention of the evolution of a certain species – in this case the Anopheles Mosquito. Editing the genome of this species to reduce populations could save many lives. Bill Gates has also stated that he has ambitious plans to ensure that genetically modified mosquitos are to be released in the wild within a few years, providing all the safety checks permit and potential ethical issues are identified and resolved.
Arguably the most important impact of this revolutionary technique lies in the potential it has to cure genetic diseases such as cancer. A Chinese team of researchers based in Sichuan University, led by Lu You, has already been given the green light to begin the first human trials – possibly before the end of the year. The main purpose of this first wave of trials will be to ensure that this technology is safe to use and subsequent trials will develop the effectiveness of the therapy itself. The therapy involves the removal of T cells (a type of white blood cell that is essential to our immune system) from the patient and then three CRISPR edits will be performed on the cells before they are introduced back into the body. The first will add a gene that contains a protein engineered to detect cancerous cells and instruct T cells to target them. The second modification will involve the removal of a naturally occurring protein that could prevent the first one from working and the third edit will be a defence mechanism to help prevent cancer cells from disabling the T cell.
Figure 1 Cancer cell (pink) being attacked by T cell.
There is a seemingly endless amount of possibilities that this new discovery could lead to and there will no doubt be an explosion in genetic engineering research in the coming years. In addition to its medical and agricultural applications, it could also be used to bring sci-fi to reality. Designer babies could finally be on the way and the Chinese have already successfully performed a gene edit on a foetus. Cloning may also be possible with this discovery. Harvard Medical Professor George Church and a research team have used CRISPR editing to explore ways of cloning Woolly Mammoths by taking genetic segments from frozen specimens and introducing them into the sequence of an Asian Elephant. It is truly frightening to think what the future holds for molecular biology now this technology has been used and will continue to be used however it has already proven to be one of the most ground-breaking developments in the field since the mapping of the genome and may mark the beginning of something truly amazing.