A gene is a DNA code that contains some accurate information that determines a particular characteristic in a given crop. Genetic modification of crop plants refers to the process by which a DNA from a different plant or animal is introduced to another plant. The new gene introduced leads to a permanent change in the genetic makeup of the cell to which the new DNA is introduced (Freedman, 2009).
According to Chrispeels, Sadava and Chris peels (2003), there are several steps through which genetic modification of crops is done. The gene is first isolated from the plant or an animal containing it. This process is aided by the knowledge of the structure, location and function of the gene. It involves seeing whether there is a linkage between the phenotype of interest and a precisely known part of the genome. The whole chromosomes to which all DNA are found is carefully studied until it is narrowed down to the correct sequence of interest after which the researchers extract the sequence of interest. This process is called mapping.
The isolated gene is then inserted into a transfer vector. A plant pathogen bacterium called Agrobacterium tumefacien is used in the gene insertion into a plant. The gene is implanted into the bacterium using DNA techniques. For the bacterium to successfully carry the gene to be transported, most of its tumor-inducing genes are removed from its left and right sides. The border sequences left integrates the new gene into the genome of the new plant.
Agrobacterium tumefacien cells, which have plasmids with the new gene, can also be mixed with some plant cells or cut pieces of plants like leaves and stems. Through mixing, some cells take a piece of plasmid called transferred-DNA. In the process, the Agrobacterium tumefacien inserts the desired gene into the plant’s chromosome leading to the formation of genetically modified cells in the chromosome. The gene can also be inserted into the plant using a gene gun. In this process, gold particles coated with DNA cells are fired into the cells of the plant to be modified. These gold particles pass through the cell walls of the plant to which it is fired and proceeds to the cell's nucleus where integrates itself into the chromosome of the plant.
After insertion, the plant cell with the new gene is identified. Marker genes are used in this process. For instance, herbicide and antibiotic resistance genes are inserted into the vector and transferred with the desired gene. This favors the growth of the transformed genes only when the cells are exposed to antibiotics or herbicides. Since it is only the transformed cells that survive, they are then obtained and used to generate a modified plant using tissue culture method (Carter, Moschini and Sheldon, 2011).
Regeneration of the selected modified cells into a whole plant through tissue culture is done by placing the plant parts into a media containing nutrients. The nutrients induce the development of cells into various parts of the plant. The plant developed is rooted and transferred to favorable conditions where it is monitored as it grows.
The inserted fragment is then verified and characterized. Verification aims at confirming that the gene has been correctly inserted and inherited. Various tests are then done to find out the number of copies inserted and their impact on the local genes. All these processes are aimed at confirming whether the gene is functional or not.
The plant’s performance is then tested. Testing is done in the greenhouse or screen house to find whetherthe crop has acquired some other unwanted traits. Those that qualify from the greenhouse are taken to the field for further testing. In the field, they are planted in some confined places to check whether the plant can cope with an open environment. If the plant passes the test, it is taken to different environments before it is considered for commercial production.
According to Chrispeels, Sadava, et al. (2003), the genetic modification process of crop plants is made possible because the genes of all plants and animals are made up of the same molecule, DNA. Freedman, (2009) says that, the discovery that certain traits could be carried down from one generation to another has facilitated genetic modification of crops. DNA marker technologies have greatly enhanced understanding of natural variations in genetics, and this has contributed to crop modification.
The direct gene transfer technique is similar to pollen grain transfer from the anthers to the stigma only that in artificial modification, genes are directly inserted into a chromosome using scientific knowledge. The desired genome is then picked from the subsequent generations of the modified plant. Were it not for the knowledge of the gene, its function, its location and how it exists, the genetic modification of crop plants could not exist (Carter et al., 2011).
There are several reasons as to why scientists and researchers are working hard to come up with genetically modified crops. The aim of modification is to insert new traits to a crop, which does not naturally occur in the plant. Examples of traits added to plants include resistance to certain pests and diseases, resistance to herbicides, or improving certain nutrients of a crop and many more (Carter et al., 2011).
There have been a lot of concern about the safety of the modified crops. Unlike crosses where several other genes are transferred, genetic modification transfers a single desired gene to the plant leading to the better result. World Health Organization and other scientific academies in Europe have confirmed that genetically modified crops are as safe as other food crops (Carter et al., 2011).
According to Freedman, (2009), there has been an increase in the production of genetically modified crops in the recent past. Adoption of genetically modified crops has increased crop yield across the world. There is also increased profits to farmers due to high produce. It has enhanced food security, reduced use of pesticide, increased yields and reduced cost of production. This has led to overall reduction in food prices (Carter et al., 2011).
However have been claims that the modification has several health and environmental effects. There are claims that consumption of genetically consumption of modified crops might cause infertility to people, affect the immune system, and accelerate aging, development of allergies and many more. Genetically modified crops can also harm the insects, birds, and other organisms. In this case, they reduce biodiversity and lead to pollution environment. Modified crops, for instance, can transfer their traits to some weeds within the farm making them disease and insect resistant. This creates a difficulty in dealing with the weeds as they resist the impact of herbicides on them.
In my own opinion, countries should embrace the new technology because its side effects are minimal compared to the advantages it has. This is because the new technology will help reduce food crisis especially in third world countries that are experiencing much food shortage.
References
Carter, C. A., Moschini, G., & Sheldon, I. M. (2011). Genetically modified food and global welfare. Bingley, UK: Emerald.
Chrispeels, M. J., Sadava, D. E., & Chrispeels, M. J. (2003). Plants, genes, and crop biotechnology. Boston: Jones and Bartlett Publisher.
Freedman, J. (2009). Genetically modified food: How biotechnology is changing what we eat. New York, NY: Rosen Pub. Group.
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