Science of Genetic Modification

Human life is more important than economics of edible oils and certainly more precious than GM mustard or any other genetically modified edible oilseeds. — Vinod Johri

 

Recently there has been controversy over GM Mustard where Government is considering introducing harvesting GM mustard primarily to produce bumper crops of mustard to reduce oil imports on which our country heavily depends. We have already known misfortunes of genetically modified BT Cotton. Simultaneously several organizations are opposing it on several grounds including climate and health hazards of genetically modified crops, costly seeds monopolised by foreign producers and several countries having banned GM crops. People in general are wary of GM crops as they are engineered in a lab and do not occur in Nature.

Genetic Modification is a technology that involves inserting DNA into the genome of an organism. To produce a GM plant, new DNA is transferred into plant cells. Usually, the cells are then grown in tissue culture where they develop into plants. The seeds produced by these plants will inherit the new DNA. Genetically modified organisms (GMOs) are plants, animals, or microorganisms whose genetic makeup is artificially modified or altered. Individual genes can be introduced from one organism to another across species. GMOs have several purposes including resistance to certain environmental conditions, pests, and diseases or resistance to chemicals such as herbicides. Some crops are genetically modified to increase their value. Despite biotech industry promises, no evidence shows any GMOs currently on the market showing increased yield, enhanced nutrition, drought tolerance, or any other consumer benefit. The safety of GMOs is generally unknown. There is a lack of credible independent long-term feeding studies. An increasing number of people around the world are choosing to eat organic and non-GMO products.

There are 3 main types of genetic modifications :

1.    Transgenic – Plants have genes inserted into them that are derived from other species. 
2.    Cisgenic – Plants are made using genes of the same species or closely related. 
3.    Subgeneric – To alter genetic formation of a plant without incorporating genes from other plants. 

The characteristics of all living organisms are determined by their genetic makeup and its interaction with the environment. The genetic makeup of an organism is its genome, which in all plants and animals is made of DNA. The genome contains genes, regions of DNA that usually carry the instructions for making proteins. It is these proteins that give the plant its characteristics. For example, the colour of flowers is determined by genes that carry the instructions for making proteins involved in producing the pigments that colour petals.

Genetic modification of plants involves adding a specific stretch of DNA into the plant’s genome, giving it new or different characteristics. This could include changing the way the plant grows, or making it resistant to a particular disease. The new DNA becomes part of the GM plant’s genome which the seeds produced by these plants will contain.

The first stage in making a GM plant requires transfer of DNA into a plant cell. One of the methods used to transfer DNA is to coat the surface of small metal particles with the relevant DNA fragment, and bombard the particles into the plant cells. Another method is to use a bacterium or virus. There are many viruses and bacteria that transfer their DNA into a host cell as a normal part of their life cycle. For GM plants, the bacterium most frequently used is called Agrobacterium tumefaciens. The gene of interest is transferred into the bacterium and the bacterial cells then transfer the new DNA to the genome of the plant cells. The plant cells that have successfully taken up the DNA are then grown to create a new plant. This is possible because individual plant cells have an impressive capacity to generate entire plants. On rare occasions, the process of DNA transfer can happen without deliberate human intervention. For example, the sweet potato contains DNA sequences that were transferred thousands of years ago, from Agrobacterium bacteria into the sweet potato genome.

Risks and Controversies Surrounding the Use of GMOs

Despite the fact that the genes being transferred occur naturally in other species, there are unknown consequences to altering the natural state of an organism through foreign gene expression. After all, such alterations can change theorganism’s metabolism, growth rate and response to external environmental factors. These consequences influence not only the GMO itself, but also the natural environment in which that organism is allowed to proliferate. Potential health risks to humans include the possibility of exposure to new allergens in genetically modified foods, as well as the transfer of antibiotic-resistant genes to gut flora.

Horizontal gene transfer of pesticide, herbicide, or antibiotic resistance to other organisms would not only put humans at risk, but it would also cause ecological imbalances, allowing previously innocuous plants to grow uncontrolled, thus promoting the spread of disease among both plants and animals. Although the possibility of horizontal gene transfer between GMOs and other organisms cannot be denied, in reality, this risk is considered to be quite low. Horizontal gene transfer occurs naturally at a very low rate and, in most cases, cannot be simulated in an optimized laboratory environment without active modification of the target genome to increase susceptibility.

In contrast, the alarming consequences of vertical gene transfer between GMOs and their wild-type counterparts have been highlighted by studying transgenic fish released into wild populations of the same species. The enhanced mating advantages of the genetically modified fish led to a reduction in the viability of their offspring. Thus, when a new transgene is introduced into a wild fish population, it propagates and may eventually threaten the viability of both the wild-type and the genetically modified organisms.

Unintended Impacts on Other Species: The Bt Corn Controversy

One example of public debate over the use of a genetically modified plant involves the case of Bt corn. Bt corn expresses a protein from the bacterium Bacillus thuringiensis. Prior to construction of the recombinant corn, the protein had long been known to be toxic to a number of pestiferous insects, including the monarch caterpillar, and it had been successfully used as an environmentally friendly insecticide for several years. The benefit of the expression of this protein by corn plants is a reduction in the amount of insecticide that farmers must apply to their crops. Unfortunately, seeds containing genes for recombinant proteins can cause unintentional spread of recombinant genes or exposure of non-target organisms to new toxic compounds in the environment. The now-famous Bt corn controversy started with a laboratory study by Losey et al. (1999) in which the mortality of monarch larvae was reportedly higher when fed with milkweed covered in pollen from transgenic corn than when fed milkweed covered with pollen from regular corn. The report  was followed by another publication suggesting that natural levels of Bt corn pollen in the field were harmful to monarchs.

Unintended Economic Consequences

Another concern associated with GMOs is that private companies will claim ownership of the organisms they create and not share them at a reasonable cost with the public. If these claims are correct, it is argued that use of genetically modified crops will hurt the economy and environment, because monoculture practices by large-scale farm production centreswill dominate over the diversity contributed by small farmers who can’t afford the technology. 

Why is there tough opposition to GM crops?

1.    Genetically engineered foods often present unintended side effects. Genetic engineering is a new field, and long-term results are unclear. Very little testing has been done on GM food.
2.    Some crops have been engineered to create their own toxins against pests. This may harm non-targets such as farm animals that ingest them. The toxins can also cause allergy and affect digestion in humans.
3.    GM crops are modified to include antibiotics to kill germs and pests.  When we consume them, these antibiotic markers will remain in our body and will render actual antibiotic medications less effective over a period of time, leading to superbug threats. This means illnesses will become more difficult to cure.
4.    Besides health and environmental concerns, certain pointson social and economic issues have been raised. They have voiced serious concern about multinational agribusiness companies taking over farming from the hands of small farmers. 
5.    Farmers are reluctant because they will have limited rights to retain and reuse seeds. Dependence on GM seed companies could prove to be a financial burden for farmers.Their concern also includes finding a market that would accept GM food.

In the European Union several countries have banned GMOS i.e. France, Germany, Austria, Greece, Hungary, the Netherlands, Latvia, Lithuania, Luxembourg, Bulgaria, Poland, Denmark, Malta, Slovenia, Italy, and Croatia. In Africa, Algeria and Madagascar have banned GMOs, and in Asia, Turkey, Kyrgyzstan, Bhutan, and Saudi Arabia. Belize, Ecuador, Peru, and Venezuela have all banned GMOs. The United States has no official legislation banning GMOs.

Government has taken several steps to help oil seed farmers, increase crop area and developing new high yield variants of oil seeds. A financial outlay of Rs.11,040 crore has been made for boosting palm oil production.It is proposed to cover an additional area of 6.5 lakh hectare for oil palm till the year 2025-26 and thereby reaching the target of 10 lakh hectares ultimately.  The production of Crude Palm Oil (CPO) is expected to go upto 11.20 lakh tonnes by 2025-26 and upto 28 lakh tonnes by 2029-30.

We produce more food today without the use of GM technology than is required to feed the world population, and we do not need GM technology to take care of future food requirements. We have virtually no testing of GM crops for safety on humans and certainly not on long term testing of harmful biological effects of genetic modification on humans. Human life is more important than economics of edible oils and certainly more precious than GM mustard or any other genetically modified edible oilseeds. qq

Vinod Johri: Retd. Additional Commissioner of Income Tax, Delhi

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