Genome Editing

Over the last few decades, various techniques have been developed to alter the properties of plants and animals. While the targeted transfer of recombinant DNA into crop plants remains a valuable tool to achieve a desirable breeding outcome, integration of transgenes into the host genome has been random, which in part, leads to reduced acceptance of GMOs by the general population in some parts of the world. Likewise, methods of induced mutagenesis, such as TILLING, have the disadvantage that many mutations are induced per plant, which has to be removed again by expensive backcrossing. Advances in genome sequencing have provided more and more information on differences between susceptible and resistant varieties, which can now be directly targeted and modified using CRISPR/Cas9 technology. By selecting specific gRNAs occurrence of off-target modifications are comparatively low. ZFNs and TALENs- based approaches required re-engineering a new set of assembled polypeptides for every new target site for each experiment. The difficulty in cloning and protein engineering prevented these tools from being broadly adopted by the scientific community. Compared to these technologies, designing the CRISPR toolbox is much simpler and more flexible. CRISPR/Cas9 is versatile, less expensive and highly efficient. It has become the most widely used technology for genome editing in many organisms.