Genome editing (also called gene editing) is a group of technologies that give scientists the ability to change an organism’s DNA. These technologies allow genetic material to be added, removed, or altered at particular locations in the genome. Several approaches to genome editing have been developed. A recent one is known as CRISPR-Cas9, which is short for clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9. The CRISPR-Cas9 system has generated a lot of excitement in the scientific community because it is faster, cheaper, more accurate, and more efficient than other existing genome editing methods.
CRISPR-Cas9 was adapted from a naturally occurring genome editing system in bacteria. The bacteria capture snippets of DNA from invading viruses and use them to create DNA segments known as CRISPR arrays. The CRISPR arrays allow the bacteria to “remember” the viruses (or closely related ones). If the viruses attack again, the bacteria produce RNA segments from the CRISPR arrays to target the viruses’ DNA. The bacteria then use Cas9 or a similar enzyme to cut the DNA apart, which disables the virus. The CRISPR-Cas9 system works similarly in the lab.
Applications of the technology
- The technology can be used in many industrial processes that use bacterial cultures. It can be used to make bacterial cultures more resistant to attacks from viruses. This will increase the productivity. It can also be used for quality and quantity improvement of foods like cheese and yoghurt.
- In agriculture it will help in design of new variety of grains, roots and fruits.
- The technology has been used to remove, insert and modify DNA in human cells and other animal cells grown in petri dishes.
- The technology is also used to create transgenic animals such as rats, mice, pigs and primates. Recently, scientists reported the successful use of the technology for prevention of muscular dystrophy and cure a rare liver disease in mice. The technology is also being used to make human cells immune to HIV. Malaria-resistant mosquitos are also being developed.
- Scientists are also working to create human organs from transgenic pigs by use of this technology in conjunction with pluripotent stem cells. This will helps us to solve some of the shortage of human organs for transplant operations and also in overcoming some of the side effects caused by organ transplantation such as graft-versus host disease.
- In context of health, the technology can help us to develop new treatments for rare metabolic disorders and genetic diseases ranging from haemophilia to Huntingdon’s disease.
- The technology is also being investigated to develop new methods in gene therapy to provide remedies for simple genetic disorders like sickle-cell anemia and eventually curing more complex diseases involving multiple genes.
Editing sperm cells or eggs—known as germline manipulation—would introduce inheritable genetic changes at inception. This could be used to eliminate genetic diseases, but it could also be a way to ensure that your offspring have blue eyes, say, and a high IQ. As a result, several scientific organizations and the National Institutes of Health have called for a moratorium on such experimentation.
Using a CRISPR-related technique known as gene drive, bioengineers can encode DNA with a selected-for trait, which propagates to future generations—and across entire populations—with unnatural speed. This could give mosquitoes resistance to a parasite responsible for malaria or encode them with a gene for female sterility—thus breeding the pests themselves out of existence. But there’s also the risk of spreading unwanted mutations and crossbreeding the change into another species. “There could be real dangers to releasing organisms into the environment that are out of control at some level genetically,”