CRISPR / Gene Editing

Subject- Science and Technology

Source- The Hindu

Reference

• Recently, the gene-editing technology which has led to innovations in medicine, evolution and agriculture has completed 10 years of innovation.
  

About Gene Editing

• A decade ago, scientists in Germany and the US discovered a technique which allowed them to ‘cut’ DNA strands and edit genes.
  
• Gene/genome editing refers to technology that permits to change an organism’s DNA.
  

1. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome.
   
2. Its applications include correcting genetic defects, treating and preventing the spread of diseases and improving crops etc.
   

• Advanced research has allowed scientists to develop the highly effective clustered regularly interspaced palindromic repeat (CRISPR) -associated proteins-based systems.
  

1. This system allows for targeted intervention at the genome sequence.
   
2. This tool has opened up various possibilities in plant breeding. Using this tool, agricultural scientists can now edit the genome to insert specific traits in the gene sequence.
   

• Depending on the nature of the edit that is carried out, the process is divided into three categories — SDN 1, SDN 2 and SDN 3.
  

1. SDN1 introduces changes in the host genome’s DNA through small insertions/deletions without introduction of foreign genetic material.
   
2. In the case of SDN 2, the edit involves using a small DNA template to generate specific changes.
   
3. The SDN3 process involves larger DNA elements or full length genes of foreign origin which makes it similar to genetically modified organisms (GMO) development.
   

Applications

• Researchers have been able to modify the genomes of specific tissues such as liver and brain tissues using hydrodynamic injection and adeno-associated virus (AAV).
  
• CRISPR-Cas9 can be used to generate mutants for target genes.
  
• CRISPR-Cas9 can be used to create animal models to mimic human diseases and to understand disease development by mutating or silencing genes.
  
• CRISPR-Cas9 can be applied to cells in vivo or ex vivo. In the in vivo approach, CRISPR-Cas9 is directly transferred to cells in the body using either viral or nonviral methods. In the ex vivo approach, first the cells are removed from the body; then CRISPR is applied to the cells and they are transferred back to the body.
  
• CRISPR was first used for commercial purposes to make bacterial cultures used in cheese and yoghurt production resistant to viral infections.
  
• Single-stranded RNA (ssRNA) sequences can also be edited by CRISPR-Cas9.
  
• These studies are commonly focused on increasing the tolerance of soldiers against biological or chemical warfare. This technology has the potential to influence human performance optimization.