Genetic modification refers to techniques used to manipulate the genetic composition of an organism by adding specific useful genes. A gene is a sequence of DNA that contains information that determines a particular characteristic/trait. All organisms have DNA (genes). Genes are located in chromosomes. Genes are units of inheritance that are passed from one generation to the next and provide instructions for development and function of the organism. Crops that are developed through genetic modification are referred to as genetically modified (GM) crops, transgenic crops or genetically engineered (GE) crops.
Over the last 30 years, the field of genetic engineering has developed rapidly due to the greater understanding of deoxyribonucleic acid (DNA) as the chemical double helix code from which genes are made. The term genetic engineering is used to describe the process by which the genetic makeup of an organism can be altered using “recombinant DNA technology.” This involves the use of laboratory tools to insert, alter, or cut out pieces of DNA that contain one or more genes of interest.
Genetically Modified crops
Genetically modified crops (GMCs, GM crops, or biotech crops) are plants used in agriculture, the DNA of which has been modified using genetic engineering techniques. In most cases the aim is to introduce a new trait to the plant which does not occur naturally in the species. Examples in food crops include resistance to certain pests, diseases, or environmental conditions, reduction of spoilage, or resistance to chemical treatments (e.g. resistance to a herbicide), or improving the nutrient profile of the crop.
Development of transgenic crops
Although there are many diverse and complex techniques involved in genetic engineering, its basic principles are reasonably simple. There are five major steps in the development of a genetically engineered crop. But for every step, it is very important to know the biochemical and physiological mechanisms of action, regulation of gene expression, and safety of the gene and the gene product to be utilized. Even before a genetically engineered crop is made available for commercial use, it has to pass through rigorous safety and risk assessment procedures.
The first step is the extraction of DNA from the organism known to have the trait of interest. The second step is gene cloning, which will isolate the gene of interest from the entire extracted DNA, followed by mass-production of the cloned gene in a host cell. Once it is cloned, the gene of interest is designed and packaged so that it can be controlled and properly expressed once inside the host plant. The modified gene will then be mass-produced in a host cell in order to make thousands of copies. When the gene package is ready, it can then be introduced into the cells of the plant being modified through a process called transformation. The most common methods used to introduce the gene package into plant cells include biolistic transformation (using a gene gun) or Agrobacterium-mediated transformation. Once the inserted gene inserted stable, inherited, and expressed in subsequent generations, then the plant is considered a transgenic. Backcross breeding is the final step in the genetic engineering process, where the transgenic crop is bred and selected in order to obtain high quality plants that express the inserted gene in a desired manner.
The length of time in developing transgenic plant depends upon the gene, crop species, available resources, and regulatory approval. It may take 6-15 years before a new transgenic hybrid is ready for commercial release.
GM crops grown today, or under experimental development, have been modified with traits intended to provide benefit to farmers, consumers, or industry. These traits include improved shelf life, disease resistance, stress resistance, herbicide resistance, and pest resistance, production of useful goods such as biofuel or drugs, and ability to absorb toxins, for use in bioremediation of pollution.
Regulation of the release of genetically modified crops
Governments have taken different approaches to assess and manage the risks associated with the use of engineering technology and the development and release of genetically modified organisms (GMO), including genetically modified crops and genetically modified fish. There are differences in the regulation of GMOs between countries, with some of the most marked differences occurring between the USA and Europe. Regulation varies in a given country depending on the intended use of the products of the genetic engineering. For example, a crop not intended for food use is generally not reviewed by authorities responsible for food safety. The basic concepts for the safety assessment of foods derived from GMOs have been developed in close collaboration under the auspices of the Organization for Economic Co-operation and Development (OECD) and the United Nations' World Health Organization(WHO) and Food and Agricultural Organization (FAO). In 2003 the Codex Alimentarius Commission of the FAO/WHO adopted a set of "Principles and Guidelines on foods derived from biotechnology" to help countries coordinate and standardize regulation of GM food to help ensure public safety and facilitate international trade and updated its guidelines for import and export of food in 2004.
The release of transgenic crops in India is governed by the Indian Environment Protection Act, which was enacted in 1986. The Institutional Biosafety Committee (IBSC), Review Committee on Genetic Manipulation (RCGM) and Genetic Engineering Approval Committee (GEAC) all review any genetically modified organism to be released, with transgenic crops also needing permission from the Ministry of Agriculture. India regulators cleared the Bt Brinjal, a genetically modified eggplant, for commercialization in October 2009. Following opposition from some scientists, farmers and environmental groups a moratorium was imposed on its release in February 2010.There have been four official reports on GMO in India till August 2013 ,1)The ‘Jairam Ramesh Report’ - February 2010, imposing an indefinite moratorium on Bt Brinjal 2) The Sopory Committee Report - August 2012. 3) The Parliamentary Standing Committee (PSC) Report on GM crops - August 2012. 4) Final Report of The Technical Expert Committee established by Supreme Court - July 2013.
Author: Dr. Sujata Roy
Rajalakshmi Engineering College, Chennai