CRISPR – briefly explained


CRISPR stands for ‘Clustered Regularly Interspaced Short Palindromic Repeats’ and it is originally a bacterial immune system that confers resistance to foreign genetic elements such as those from viral infections. Recently, CRISPR technology has emerged as a powerful tool for targeted genome modification in virtually any species. It allows scientists to make changes in the DNA in cells that has the potential to cure genetic diseases in animals or develop new traits in plants. The technology works through a protein called Cas9 that is bound to an RNA molecule and thus forming a complex. RNA is a chemical cousin of DNA and it enables interaction with DNA molecules that have a matching sequence. The complex functions like a sentinel in the cell and searches through the entire DNA in the cell that matches the sequences in the bound RNA. When the sites are found, it allows the protein complex to cut and break DNA at that site. Its success is much due to its ability to be easy programmable to target different sites.

It differs from classic genetic engineering techniques because it opens up the opportunity for target modification, or the modification of specific regions and sequences in the genome. Because it can modify a specific gene of interest, the technology is also called gene-editing. CRISPR has the potential to operate as a stand-alone technology. However, up until now, its application in plants still relies on other genetic engineering tools (e.g. recombinant DNA, biolistic, electroporation).

Trait improvement through classic breeding in crops can be accelerated by CRISPR-based genome engineering. CRISPR has been tested in commercial crops to increase yield, improve drought tolerance, and increase growth in limited-nutrient conditions to breed crops with improved nutritional properties and to combat plant pathogens.

The opportunity to do this genome editing also raises various safety and ethical issues that have to be considered. One of the safety concerns relates to the possibility to generate permanent DNA breaks at other, unintended sites in the genome. The rules governing off-target activity of CRISPR are just beginning to be understood in more detail. In addition, CRISPR ability to edit small bits of DNA sequences generates minimal modifications, and it also makes it more difficult for regulators and farmers to identify a modified organism once it has been released. Lack of detection of CRISPR modified crops would raise concerns over labeling and consumer’s rights, as well as risk monitoring issues.

CRISPR gene-editing is likely to have similar commercial and socio-economic implications as classical genetically modified organisms. Results of gene-editing are bound to be protected by intellectual property rights and therefore have market power and purchasing power implications for seed and bio-tech companies as suppliers, on the one hand, and farmers, on the other.

(This is a text box to be published in the UN Commission on Science and Technology for Development study, which focuses on the role of science, technology and innovation in ensuring food security by 2020 in the context of the Millennium Development Goals.)

Front page photo: