CRISPR (clustered regularly interspaced short palindromic repeats) were accidentally cloned in Osaka University where its function was unknown has great potential in not only agriculture field.
We all have edited our pictures at some point in our life. We edit them when we want to remove something that we dislike in the picture or something that is destroying the picture. Editing is also done to enhance the quality and the beauty of the image. For these purposes, we use software like Photoshop, Pixlr, Microsoft Photo Editor and many other software.
Similarly, CRISPR Technology is used by bio technologists to edit genes to change the faulty gene that is causing abnormalities and diseases in human and also to edit genes in plants and other organisms to improve their production quality and quantity.
CRISPR or Cas-protein are the part of bacteria’s defense system. They consist of palindromic sequences (repeating sequences) of nucleotides that alter with the genome of the past invading viruses, left in the bacteria, by changing their DNA sequence. The bacteria then use these altered sequences to defend itself from succeeding infection from viruses.
In 2012, Jennifer Duodena and Emmanuelle Charpentier came up with a method to use Cas-protein to edit plant, animal and even human genome. This protein/enzyme is called Cas-9 protein.
CRISPR technology is now used to edit plants and animal genome especially mouse genome. It is now an aim to cure genetic diseases like Thalassemia, Blindness, AIDS, and Cancer through CRISPR technology. CRISPR Technology has a great deal of application in the agriculture field. Genome of plants are changed to increase yield, disease tolerance and grow out of season plants. Plants that are breaded through CRISPR or Cas-9 are now available in markets like pink tomatoes and different rice breeds and mushrooms.
A new development that has been made due to CRISPR technology is the ability to make “designer babies”. Parents can now conceive children with particular traits of their choice like eye colour. But this line of research is extremely controversial and many scientists avoid it.
Working of CRISPR
The CRISPR technology has been used in the variety of tasks in the past which includes removing the genes responsible for diseases, destroying drug-resistant bacteria and creating molecular recording devices. The procedure of how this technology is regulated is very simple, inexpensive and less time taking. Other gene-editing techniques are time-consuming but with CRISPR technology, what used to happen in months, is now completed in days.
The DNA sequences of the genome encode a series of messages. By genome editing, the DNA sequences are changed which in turn causes the change in the encoded message. This is achieved by inserting a cut in the DNA, breaking it and then causing the cell’s natural DNA repair mechanism to introduce the change required. CRISPR-Cas9 provides a measure to do so. Cas9 can be directed to cut the DNA. This is done by changing the nucleotide sequence of cDNA. This binds to the target on the complementary DNA. The two main components needed for gene-editing are:
- A guide RNA
- The Cas9 protein
Basically, in operation, we design a band of twenty base pairs of nucleotides that match the gene we want to edit. Then an RNA molecule is constructed which is complementary to these 20 base pairs. The RNA together with Cas9 acts as a pair of scissors for DNA cutting.
Once the DNA cutting is done, the cell’s natural repair mechanisms are triggered which starts the work of introducing mutations or the other changes required in the genome. This process can be done in two ways. One method of repairing the broken DNA is to simply glue the two cuts back together. This method is known as “non-homologous end-joining”. This disrupts gene resulting in the mutation as nucleotides are accidentally inserted or deleted.
The second method is usually preferred in which the cut in the DNA is repaired by filling in the new sequence of nucleotides in the gap. A strand of DNA is needed as a template for this process. This strand can be supplied by the scientists, of their choice, resulting in the correction of a mutation or writing in any gene they want.
The modern gene-editing kit of CRISPR consists of bottles of special proteins which are small enough to be placed on the shelf of a fridge, a few Petri dishes, and pipettes.
This amazing technology also has the potential of treating and preventing diseases by the transformation of medicines. Trials are being done to implement this on the diseases namely, cancer, blood disorders, blindness, AIDS, cystic fibrosis, muscular dystrophy, and Huntington’s disease.
Application of CRISPR technology in the field of agriculture:
The world population is rapidly increasing with increased demands for food and other resources. The growing climate change has caused the increased abiotic stresses and the outbreak of pests which is risking the efficient crop production.
CRISPR/Cas9 technology is extensively being used in agriculture for this reason. It provides a great opportunity for biotechnologists to develop a sustainable and productive agricultural system by working on the improvement of crop yield, abiotic stress tolerance, increasing resistance to diseases and pests and improvement of the plant product by modifying the plants. By using CRISPR a group of scientists at Cold Spring Harbor Laboratory of USA engineered the promoter sequence of genes in tomato.
Moreover, increased seed size in wheat along with the production of transgene-free low-gluten wheat has been done by the process of CRISPR technology. It can also be used to give rise to the variations in plants whose natural variation is halted or not available. There are many similar examples showing the successful implementation of this technology in agriculture. Due to its application, the improvement of crop yields in tropical regions is remarkable in the last five years.
Thus, it is evident that the use of CRISPR technology will lead to success in the improvement of agriculture in future as genome-editing has shown great potential for the enhancement of crop plants to meet the growing global demands of food.
Future of CRISPR technology
CRISPR technology has great potential in not only agriculture field but also in farm animal improvement and human gene editing. Although it is a new technique, but in the past few years numerous researches have been done and many are in process. It is said that CRISPR technique can even make it possible to end genetic disorders but it is not an easy process as many genes are linked together and change in one DNA nucleotide sequence can cause lethal effects.