Gene Editing and The Future of Food

With each passing minute, the world population increases by hundreds, and to support the ever-increasing population, food is required. To cope up with this food demand, various methods are being devised since decades. A recent one under discussion is ‘Gene Editing’.

This method, unlike any other method, is based on the natural processes in plants, i.e. the cell’s basic machinery, which allows researchers to cut out specific or ‘unwanted’ parts of DNA in order to control the traits in plants as required. The cell’s machinery repairs itself automatically and then functions as a normal cell.

Gene Editing involves a method known as CRISPR – Clustered Regularly Interspaced Short Palindromic Repeats or CRISPR Cas9. Cas9 here is the enzyme produced by Crispr system which binds to the DNA and cuts it, shutting the targeted gene off. In some cases, Cas3 enzyme can also be used. There’s one called Sherlock which targets RNA instead of DNA.

First reported in Archaea by Francisco Mojica, a Spanish scientist, in 1993, CRISPR’s were identified as a part of the bacterial immune system. These consisted of repeating gene sequences with spacers (non coding sequences of DNA) in between them. Different researchers, working independently then published similar findings. Feng Zhang from Broad Institute of MIT and Harvard, McGovern Institute for Brain Research at MIT, Massachusetts

Was the first to successfully use CRISPR Cas9 for genome editing in eukaryotic cells. It involves the following mechanism:

1. The gene of interest is firstly identified and accordingly its complementary RNA (known as ‘guide RNA’) and enzyme is created.
2. The guide RNA and enzyme are then introduced into the cell.
3. Guide RNA then locates and binds to its paired DNA sequence and the Cas9 enzyme.
4. The enzyme cuts across the strands of DNA and removes the sequence due to which a mutation is introduced.
5. After removal of the sequence, cell repairs itself, and guide RNA and enzyme are removed.
6. This resulting plant is then crossed with the original one, same as traditional breeding.

The advantage of this technique is that CRISPR’s do not need to be paired with separate cleaving enzymes, since it is capable of cutting the DNA strands on its own. It can target multiple genes simultaneously, and since it doesn’t involve introduction of genes from other species, it is much simpler, cheaper and faster process than the GMO’s developed by traditional breeding methods.

It was used in developing various crops with desirable traits, Lippmann’s tomatoes being a popular one, created by Zach Lippmann, a plant biologist in New York and Van Eck, his collaborator at the Boyce Thompson Institute in Ithaca, New York. They experimented different genes in the tomato plant to study every desirable trait possible. This led in developing tomatoes that are more nutritious, resistant to pests, and which can adapt to irregularly changing climatic conditions. Also, their branching is modified by lowering the activity of certain genes in a way that the tomatoes will be easier to pluck from the plant.

The technique helped in producing satisfactory results in less than a year, which gave some hope that better varieties can be developed in a more efficient manner and can address to the problem of food shortage. CRISPR was used in many other food crops, some of which are,

1. Wheat: To produce crops with low gluten content.
2. Corn: To develop modified variety which can produce more grain under drought conditions.
3. Coffee: To produce a variety which is naturally decaffeinated.

Other applications of CRISPR method can be seen in animal livestock to create healthier meat without relying on antibiotics, which are frequently used in animals and can in turn harm humans. It is also used majorly in correcting genetic diseases.

The technique created a talk among researchers, spreading rapidly from US and Europe to developing nations. So, it is applied in other food products to enhance food production. Still a significant group of people believe that gene edited crops shouldn’t be consumed, thinking it is unsafe since they have the same notion regarding GMO’s, considering inserting or deleting genes or tampering with original species as unnatural. Whether or not to use, it can only be confirmed with time. Till then, the debate continues.