Basics of Genetic Modification

Chapter I

Basics of Genetic Modification

Although "biotechnology" and "genetic modification" commonly are used interchangeably, GM is a special set of technologies that alter the genetic makeup of such living organisms as animals, plants, or bacteria. Biotechnology, a more general term, refers to using living organisms or their components, such as enzymes, to make products that include wine, cheese, beer, and yogurt.

Combining genes from different organisms is known as recombinant DNA technology, and the resulting organism is said to be "genetically modified," "genetically engineered," or "transgenic." GM products (current or in the pipeline) include medicines and vaccines, foods and food ingredients, feeds, and fibers.

Locating genes for important traits—such as those conferring insect resistance or desired nutrients—is one of the most limiting steps in the process. However, genome sequencing and discovery programs for hundreds of different organisms are generating detailed maps along with data-analyzing technologies to understand and use them.

In 2006, a total of 252 million acres of transgenic crops were planted in 22 countries by 10.3 million farmers. The majority of these crops were herbicide- and insect-resistant soybeans, corn, cotton, canola, and alfalfa. Other crops grown commercially or field-tested are a sweet potato resistant to a virus that could decimate most of the African harvest, rice with increased iron and vitamins that may alleviate chronic malnutrition in Asian countries, and a variety of plants able to survive weather extremes.

On the horizon are bananas that produce human vaccines against infectious diseases such as hepatitis B; fish that mature more quickly; cows that are resistant to bovine spongiform encephalopathy (mad cow disease); fruit and nut trees that yield years earlier, and plants that produce new plastics with unique properties.

In 2006, countries that grew 97% of the global transgenic crops were the United States (53%), Argentina (17%), Brazil (11%), Canada (6%), India (4%), China (3%), Paraguay (2%) and South Africa (1%). Although growth is expected to plateau in industrialized countries, it is increasing in developing countries. The next decade will see exponential progress in GM product development as researchers gain increasing and unprecedented access to genomic resources that are applicable to organisms beyond the scope of individual projects.

Technologies for genetically modifying (GM) foods offer dramatic promise for meeting some areas of greatest challenge for the 21st century. Like all new technologies, they also poses some risks, both known and unknown. Controversies surrounding GM foods and crops commonly focus on human and environmental safety, labeling and consumer choice, intellectual property rights, ethics, food security, poverty reduction, and environmental conservation.¹
Let us look at the meaning of some common terms.

What is biotechnology?

Answer: Biotechnology means the application of scientific and engineering principles to the processing of materials by biological agents to produce goods and services.² Broadly speaking, biotechnology is any technique that uses living organisms or substances from these organisms to make or modify a product for a practical purpose. Biotechnology can be applied to all classes of organism - from viruses and bacteria to plants and animals - and it is becoming a major feature of modern medicine, agriculture and industry. Modern agricultural biotechnology includes a range of tools that scientists employ to understand and manipulate the genetic make-up of organisms for use in the production or processing of agricultural products.³

The Convention on Biological Diversity (CBD) defines biotechnology as: “any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products for specific use” (Secretariat of the Convention on Biological Diversity, 1992). This definition includes medical and industrial applications as well as many of the tools and techniques that are commonplace in agriculture and food production.

What is Modern Biotechnology?

Answer: The Cartagena Protocol on Biosafety defines “modern biotechnology” more narrowly as the application of:
(a) In vitro nucleic acid techniques, including recombinant deoxyribonucleic acid (DNA) and direct injection of nucleic acid into cells or organelles, or
(b) Fusion of cells beyond the taxonomic family, that overcome natural physiological reproductive or recombination barriers and that are not techniques used in traditional breeding and selection.⁴

What is Biotechnology in Agriculture?

Answer: Biotechnology in agriculture is a collection of scientific techniques, including genetic engineering, which is used to improve or modify plants and microorganisms. The scientific foundations of biotech agriculture include not only basic plant biology but the knowledge gained in recent decades on the information contained in DNA and the particular functions of genetic material in nature.⁵

What is Genes?

Answer: Genes are the inherited blueprints for the thousands of proteins that form the building blocks of all life, from bacteria to humans. Proteins make enzymes, which carry out all the bodily processes, like digestion of food, that keep us alive. ⁶ A gene is the physical and functional unit of heredity of transmitted from generation to generation during sexual and asexual reproduction. A gene is a linear segment of a DNA that is made up of nucleotide basis in an ordered sequence that specifies the structure of a protein or has a defined function. ⁷

What is DNA?

Answer: All living things are made up of cells that are programmed by genetic material called deoxyribonucleic acid (DNA). Only a small fraction of the DNA chain actually makes up genes, which in turn code for proteins, and the remaining share of the DNA represents non-coding sequences whose role is not yet clearly understood. The genetic material is organized into pairs of chromosomes. For example, there are five chromosome pairs in the much-studied mustard species Arabidopsis thaliana. An organism's entire set of chromosomes is called the genome. The Human Genome Sequencing Project has provided the agricultural research community not only with many spin-off technologies that can be applied across the board for all living organisms but also with a model for international collaboration in tackling large genome-sequencing projects for model plants such as Arabidopsis and rice.

For a refresher course in DNA, genetics and heredity, see the interactive Web site www.dnafromthebeginning.org developed by the Cold Spring Harbor Laboratory in the United States, where much of the pioneering work in genetics and genetic engineering has been performed. ⁸

What is Genetic Engineering?

Answer: Genetic engineering involves taking genes from one species and inserting them into another. For example, genes from an arctic flounder which has "antifreeze" properties may be spliced into a tomato to prevent frost damage. ⁹

The genetic engineering is a set of laboratory techniques for isolating genes from organisms, cutting and rejoining it to make new combinations, multiplying copies of the recombined genetic material and transferring it into organisms. It is also called recombinant DNA technology because it recombines genes within an organism as well as those from other organisms.¹⁰

"Genetic engineering" means the technique by which heritable material, which does not usually occur or will not occur naturally in the organism or cell concerned, generated outside the organism or the cell is inserted into said cell or organism. It shall also mean the formation of new combinations of genetic material by incorporation of a cell into a host cell, where they occur naturally (self cloning) as well as modification of an organism or in a cell by deletion and removal of parts of the heritable material. ¹¹

What is Genetic Modification?

The genetic modification involves modifying an organism genetic make up by the introduction of a gene or genes into its cells in a way that follows the transfer of the genes to successive generation. ¹²

What is a genetically modified organism (GMO)?

Answer: GMO is the broad term used to identify organisms in which the genetic material has been altered by use of molecular techniques, which does not occur naturally. It also known as genetically engineered organisms or transgenic organisms. ¹³

How Genetic Engineering is being done?

Answer: When the desired trait is found in an organism that is not sexually compatible with the host, it may be transferred using genetic engineering. In plants, the most common method for genetic engineering uses the soil bacterium Agrobacterium tumefasciens as a vector. Researchers insert the desired gene or genes into the bacterium and then infect the host plant. The desired genes are transmitted to the host along with the infection. This method is used mainly with dicot species such as tomato and potato. Some crops, particularly monocot species such as wheat and rye, are not naturally susceptible to transformation via A. tumefasciens, although the method has recently been successfully used to transform wheat and other cereals. In the most common transformation technique for these crops, the desired gene is coated on gold or tungsten particles and a “gene gun” is used literally to shoot the gene into the host at high velocity.

Three distinctive types of genetically modified crops exist: (a) “distant transfer”, in which genes are transferred between organisms of different kingdoms (e.g. bacteria into plants); (b) “close transfer”, in which genes are transferred from one species to another of the same kingdom (e.g. from one plant to another); and (c) “tweaking”, in which genes already present in the organism's genome are manipulated to change the level or pattern of expression. Once the gene has been transferred, the crop must be tested to ensure that the gene is expressed properly and is stable over several generations of breeding. This screening can usually be performed more efficiently than for conventional crosses because the nature of the gene is known, molecular methods are available to determine its localization in the genome and fewer genetic changes are involved. ¹⁴

Source of picture: Genetic Engineering in Indian Agriculture by Kavitha Kuruganti, G V Ramanjaneyulu, Centre for Sustainable Agriculture, Hyderabad, 01/04/2007
[ C.eldoc1/g74a/GE-indian-agriculture.pdf]

What is Traditional Cross breading?

Answer: Farmers and pastoralists have manipulated the genetic make-up of plants and animals since agriculture began more than 10 000 years ago. Farmers managed the process of domestication over millennia, through many cycles of selection of the best adapted individuals. This exploitation of the natural variation in biological organisms has given us the crops, plantation trees, farm animals and farmed fish of today, which often differ radically from their early ancestors. Conventional breeding, relying on the application of classic genetic principles based on the phenotype or physical characteristics of the organism concerned, has been very successful in introducing desirable traits into crop cultivars or livestock breeds from domesticated or wild relatives or mutants. In a conventional cross, whereby each parent donates half the genetic make-up of the progeny, undesirable traits may be passed on along with the desirable ones, and these undesirable traits may then have to be eliminated through successive generations of breeding. With each generation, the progeny must be tested for its growth characteristics as well as its nutritional and processing traits. Many generations may be required before the desired combination of traits is found, and time lags may be very long, especially for perennial crops such as trees and some species of livestock. Such phenotype-based selection is thus a slow, demanding process and is expensive in terms of both time and money. ¹⁵

How is GE different from Traditional breeding?

Answer: Species barriers are not usually crossed by any other breeding technology employed by agriculture scientists. For instance, in the case of Genetic Engineering, genes from a scorpion can be inserted into a Maize plant. Human genes have been inserted into rice plant. This is unnatural and such crossing of species barriers could be across animal and plant kingdoms too.

There is genetic variation happening naturally in living organisms, mostly as a response to interaction with the external environment. Genetic variation inevitably gives rise to novelty in individual organisms. Novelty may survive and be inherited by later offspring. This process is called natural selection, in an evolutionary sense. Natural selection can be thought of as irreversible ecological change.

Natural selection is understood extremely poorly by thinking about it only in terms of genes “encoding” characteristics of individual organisms, as some proponents do. This is because most of the factors that determine the survival of organisms are external to them and are continually changing. What appears to be an individual’s genetic advantage in one ecological context may be a disadvantage in another context. The original genetic change in an individual organism is only a minor part of any event of natural selection. The ecological context of that original change, affected by all of the constellations of genes in other organisms and the way they interact, ends up being more important.
In nature, lasting genetic changes in eco-systems have happened mainly as a result of three sets of processes:
I. mutation and recombination;
II. horizontal (inter-species) gene transfer;
III. natural selection due to environmental and ecological pressures.

Selective breeding, practiced by humans for millennia, is a manipulation of the first set of processes. Genetic engineering is a manipulation and extension of the second set of processes. The natural selection processes are well understood and practiced by the farmers as part of regular farming activity. Among the existing variation, plants are selected to suit specific needs and situations. For example, India had more than 50,000 varieties of rice cultivated across the country in a variety of situations ranging from dry, hilly, waterlogged, saline conditions etc. Rice was available in different flavors, colors, sizes and suitable for different types of cooking. Modern breeding (which is now termed as conventional breeding) made the process of selection more systematic using statistical designs. From the days of selection from the naturally occurring variation science has moved to creating variation and making selections. This variation is created by crossing wild species or plants having the desired characters. Irradiation techniques to induce mutations were also tried to create variation - for example, Sharbati Sonara in wheat. In genetic engineering, as mentioned earlier, genes which code for the desired characters from selected organisms are extracted and inserted into other organisms. ¹⁶

An agricultural technology timeline ¹⁷

Technology	Era	Genetic interventions
Traditional	About 10 000 years BC	Civilizations harvested from natural biological diversity, domesticated crops and animals, began to select plant materials for propagation and animals for breeding
Traditional	About 3 000 years BC	Beer brewing, cheese making and wine fermentation
Conventional	Late nineteenth century	Identification of principles of inheritance by Gregor Mendel in 1865, laying the foundation for classical breeding methods
	1930s	Development of commercial hybrid crops
	1940s to 1960s	Use of mutagenesis, tissue culture, plant regeneration. Discovery of transformation and transduction. Discovery by Watson and Crick of the structure of DNA in 1953. Identification of genes that detach and move (transposons)
Modern	1970s	Advent of gene transfer through recombinant DNA techniques. Use of embryo rescue and protoplast fusion in plant breeding and artificial insemination in animal reproduction
	1980s	Insulin as first commercial product from gene transfer. Tissue culture for mass propagation in plants and embryo transfer in animal production
	1990s	Extensive genetic fingerprinting of a wide range of organisms. First field trials of genetically engineered plant varieties in 1990 followed by the first commercial release in 1992. Genetically engineered vaccines and hormones and cloning of animals
	2000s	Bioinformatics, genomics, proteomics, metabolomics
Source: Adapted from van der Walt (2000) and FAO (2002a).

For further details on Conventional Breeding vs Genetic Engineering ¹⁸click here

	Conventional Breeding	Genetic Engineering
Basis	The selection is among the existing variation within the species of a particular genus. Sometimes variation is introduced by using irradiation techniques. For a particular trait, selection and transfer is between alternate alleles from the existing variability.	Genes are introduced and expected to express the trait they express in native species.
Transfer	Normally inter-species and intra-generic. Sexually compatible plants are crossed and plants expressing the desired trait are selected.	Normally inter-generic.
Selection	Based on the phenotype. Plants which express the desired trait are selected. Trait based selection takes genotype and environment interaction into account.	Based on the genotype. Cells which show the presence of genes are selected. Gene based selection ignores environment interaction.

What is Maker-assisted breeding?

Answer: Genetic linkage maps can be used to locate and select for genes affecting traits of economic importance in plants or animals. The potential benefits of marker-assisted selection (MAS) are greatest for traits that are controlled by many genes, such as fruit yield, wood quality, disease resistance, milk and meat production, or body fat, and that are difficult, time-consuming or expensive to measure. Markers can also be used to increase the speed or efficiency of introducing new genes from one population to another, for example when wishing to introduce genes from wild relatives into modern plant varieties. When the desired trait is found within the same species, it may be transferred with traditional breeding methods, with molecular markers being used to track the desired gene.¹⁹

What is Biosafety?

Answer: Biosafety refers to policies and procedures adopted to avoid risk to human health and safety and to the conservation of the environment as a result of the use of GMOs for research and trade.²⁰

What is genetic pollution?

Answer: Genes engineered into plants and animals can be transferred to other species. For example, genes from GM oilseed rape, salmon or micro-organisms may move into the gene pools of wild relatives. The introduction of GM organisms into complex ecosystems may bring knock-on effects that we are unable to control. ²¹
Read More
Biotechnology and Food Security by Dr. Sujata K Dass, Isha Books, 01/01/2004
[ C.eldoc1/g74a/01jan04isa1.pdf]

Engineering Hunger by Andrew Kimbrell, The Ecologist Asia, 01/07/2003
[C.eldoc1/g74a/01jul03eca2.pdf ]

Biotechnology a basket of options by Bert Visser, LEISA, 01/12/2001
[C.eldoc1/g74a/01dec01LEISA3.pdf]

¹What are Genetically Modified (GM) Foods?, Human Genome Project Information, July 24, 2007
http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml
²Rules For The Manufacture, Use, Import, Export and Storage of Hazardous Micro Organisms Genetically Engineered Organisms or Cells (To be notified under the EP Act, 1986), Ministry of Environment & Forests Notification http://www.dbtindia.nic.in/policy/rules.html
³The State of Agriculture Report 2003-2004, Chapter 2 What is agricultural biotechnology?, Food and Agriculture Organization (FAO), 2004 [R.G74a.F2]
⁴Foods derived from modern biotechnology (2003)-A Report
http://ftp.fao.org/codex/Publications/Booklets/Biotech/Biotech_2003e.pdf
Original Source: Secretariat of the Convention on Biological Diversity, 2000
⁵Biotechnology: Finding A Practical Approach To A Promising Technology (This chaptor is taken from report G74a(28) ) by Alan Larson, Economic Perspectives, 01/10/1999 [ C.eldoc1/KICS/economic_pers1.pdf]

⁶GM Food: A Guide for the Confused, Saynotogmos.org, 01 September 2006 [C.eldoc1/g74a/01sep06say1.html]

⁷Department of biotechnology, India, FAQs, 20 May 2008
http://dbtbiosafety.nic.in/default.asp
⁸The State of Agriculture Report 2003-2004, Chapter 2 What is agricultural biotechnology?, Food and Agriculture Organization (FAO), 2004 [R.G74a.F2]

⁹GM Food: A Guide for the Confused, Saynotogmos.org, 01 September 2006 [C.eldoc1/g74a/01sep06say1.html]

¹⁰Department of biotechnology, India, FAQs, 20 May 2008 http://dbtbiosafety.nic.in/default.asp

¹¹Rules For The Manufacture, Use, Import, Export and Storage of Hazardous Micro Organisms Genetically Engineered Organisms or Cells (To be notified under the EP Act, 1986), Ministry of Environment & Forests Notification http://www.dbtindia.nic.in/policy/rules.html
¹²Department of biotechnology, India, FAQs, 20 May 2008
http://dbtbiosafety.nic.in/default.asp
¹³Department of biotechnology, India, FAQs, 20 May 2008
http://dbtbiosafety.nic.in/default.asp

¹⁴The State of Agriculture Report 2003-2004, Chapter 2 What is agricultural biotechnology?, Food and Agriculture Organization (FAO), 2004 [R.G74a.F2]

¹⁵The State of Agriculture Report 2003-2004, Chapter 2 What is agricultural biotechnology?, Food and Agriculture Organization (FAO), 2004 [R.G74a.F2]
¹⁶Genetic Engineering in Indian Agriculture by Kavitha Kuruganti, G V Ramanjaneyulu, Centre for Sustainable Agriculture, Hyderabad, 01/04/2007
[ C.eldoc1/g74a/GE-indian-agriculture.pdf]

¹⁷ Genetic Engineering in Indian Agriculture by Kavitha Kuruganti, G V Ramanjaneyulu, Centre for Sustainable Agriculture, Hyderabad, 01/04/2007
[ C.eldoc1/g74a/GE-indian-agriculture.pdf]

¹⁸Genetic Engineering in Indian Agriculture by Kavitha Kuruganti, G V Ramanjaneyulu, Centre for Sustainable Agriculture, Hyderabad, 01/04/2007
[ C.eldoc1/g74a/GE-indian-agriculture.pdf ]

¹⁹The State of Agriculture Report 2003-2004, Chapter 2 What is agricultural biotechnology?, Food and Agriculture Organization (FAO), 2004 [R.G74a.F2]
²⁰Department of biotechnology, India, FAQs, 20 May 2008
http://dbtbiosafety.nic.in/default.asp

²¹GM Food: A Guide for the Confused, Saynotogmos.org, 01 September 2006 [C.eldoc1/g74a/01sep06say1.html]