Monday, December 24, 2018

Facts Relating To A Genetically Engineered Organelle

By Paul Jackson

There have been numerous arguments for and against the use of genetically modified organisms, GMOs, in many quarters. While genetic engineering has been part of drug manufacturing for a long time, it is the use of these techniques in food production that appears to be generating a lot of jitters. Transgenic organisms appear to generate even more controversy owing to the fact that they have genetic material obtained from other species. In a bid to get safer products, researchers are now considering using a genetically engineered organelle.

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 arguably the second most important organelles in cells only second to the nucleus. Their absence within the cell means that the cell will be unable to produce energy essential for most of its processes. While alternative methods of respiration may exist, these are only effective for a limited period of time beyond which the entire cell is likely to die. Mitochondria have their own genome though it is a lot smaller than what is found in the nucleus.

A popular theory that has been advanced to explain the existence of mitochondria proposes that before they evolved fully, mitochondria existed as independent, primitive, unicellular organisms. As evolution occurred over many years, part of they lost their genome and they could no longer exist on their own. They, therefore, entered the cell and established a symbiotic relationship. This theory also attempts to explain the presence of a genome in chloroplasts.

Chloroplasts are cellular structures that play a critical role in food synthesis in most plant cells. Since the process is dependent of energy from sunlight, it is also refereed to as photosynthesis. They are also used in other processes such as synthesis of fatty acids and amino acids as well as taking part in the immune processes of plant cells. Chloroplasts have a DNA that has a circular conformation except in a few circumstances. Since chloroplasts are passed down to daughter cells, modifying their genome results in propagation of the new characteristic.

There are several steps involved in genome modification. The first involves the isolation of the desired gene. This can be done by producing it in a laboratory or obtaining it from the genome of another cell. Several genes are available in the genetic library and can easily be obtained from there. The gene is made active by addition of several elements that include, among others, promoter and terminator regions.

The next step involves insertion of the isolated gene into an organelle (mitochondria or chloroplast). If the targeted cell is a bacterium, processes such as electric shocking and thermal stimulation may be required. In animal cells, the most common technique is known as microinjection. Those used in plants include antibacterial mediated recombination, electroporation and biolistics among others.

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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