Sunday, December 23, 2018

Facts Relating To A Genetically Engineered Organelle

By Paul Jackson


The advent of genetically modified organisms, GMOs, continues to generate a heated debate in many quarters all over the world. This has particularly been fuelled by the adoption of genetic engineering techniques in food production. Transgenic organisms, which are created through exchange of genetic materials between different species of organisms are likely to cause even greater divisions. The use of a genetically engineered organelle is also possible.

For a long time, nuclear transformation has been the main technique used in genetic modification. This is, however, now changing as researchers look away from this structure and consider other organelles within the plant cell. The most ideal alternatives that have emerged are mitochondria and chloroplasts. Mitochondria are found both in animal and plant cells while chloroplasts are only present in green plants.

Mitochondria are considered the powerhouse of the cell. They produce energy necessary for most of the cell processes through a process known as oxidative phosphorylation. If they fail, the cell is at risk of dying since the alternative energy production pathways can only sustain it for a limited duration of time. Mitochondria posses a genome just like the nucleus. Their genome is, however, a lot smaller.

One of the theories that have been advanced to explain the presence of genetic material in mitochondria proposes that they were initially independent primitive organisms. They were largely parasitic depending on other unicellular organisms for most of their functions. As they evolved over thousands of years, some of their genome was lost and they could, therefore, not exist on their own. They entered the cell and started a symbiotic relationship. This theory has also been used for chloroplasts.

Chloroplasts are vital to the process of photosynthesis. This is a process that occurs in green plants and involves the use of sunlight energy in food production by a plant cell. These structures have also been established to also play a vital role in processes such as fatty acid synthesis, amino acid synthesis and mounting immune responses by the cells. Chloroplasts posses a DNA that takes on a circular conformation in most cells. Genetic modification of this DNA is passed on to daughter cells through inheritance.

Genome modification involves several steps. The first is gene isolation. This is where the desired gene is identified and obtained either from another cell or by synthesis. Several copies of genes have been studied and isolated and are now available in the genetic library. This may serve as an alternative source. Addition of various elements such as promoter and terminator regions makes the gene active.

Once the gene has been isolated, the next step is to have it inserted into the organelle. This may either be the mitochondria or the chloroplast depending on the organism. For bacterial organisms, this process may be aided by either electric shocking or thermal stimulation. Animal cells are modified through microinjection while plant cells may be subjected to agrobacteria mediated recombination, biolistics or electroporation.

Insertion of a genetic material into one cell only achieves a change in this cell. The next step is therefore to facilitate regeneration of the entire organism from this single cell. The process used for this in plants is known as tissue culture. In animals the cells used are usually stem cells so these would subsequently undergo cell division and cell growth.




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