Genetic manipulation, is a direct process that is done by manipulating or changing the genome of an organism in order for a desired trait to be produced. For this process to occur, a scientist must be able to manipulate DNA so that changes can be induced into the gene expression of the organism. Humans have be using genetic manipulation for thousands of years and it is a very controversial subject particularly when the manipulation will have an effect on humans. There are two ways in which genetic manipulation occurs, these are gene modification and transgenesis.
Gene Modification is the process that alters the genetic makeup of an organism using laboratory techniques. For example, new genes can be added or the function of the current genes can be changed. The alteration in the gene as a result of genetic modification allows for the organism to reproduce and pass on the modified genes to the next generation (New Zealand Government , n.d.). The purpose of genetic modification is to create an organism with a desired trait. For example, in crops, genetically modifying their genetic makeup allows them to develop a resistance to pests, diseases or environmental conditions. This allows for farmers to produce crops at a faster rate. A number of techniques are required for the modification of genes – they are as follows:
- DNA sequencing
- CRISPR/Cas9
- Vector Used
- Gene Drive
The two that will be explained in further detail are CRISPR/CAS9 and gene drive.
CRISPR/CAS9
CRISPR/CaS9 is a fairly new technique that is very precise. The purpose of CRISPR/Cas9 is to allow scientists to easily change DNA sequences and gene functions of organism which allows for the potential to correct genetic defects or treat and prevent diseases. Scientists can modify organisms by silencing genes by snipping them out but using repair enzymes to put desired genes in place of what is taken out.
CRISPR stands for Clustered Regularly Interspaced Short Palindromic Repeats These clusters are found in the DNA of bacteria and play a vital part in the immune system of the bacteria. Bacteria produces enzymes that fight them viruses. When these enzymes kill off the virus, smaller enzymes come and take the remaining of the virus’s genetic code and cut it into tiny pieces to them be stored in CRISPR spaces in the genome of the bacteria. These CRISPR spaces act as a place for the bacteria’s genetic information to be stored so that when a new virus comes, special attack enzymes called Cas9 carry the previous viral codes so that if the RNA of the new virus matches with any of this code the Cas9 enzyme will start to chop up this virus’s code into small pieces (Plumer, Barclay, Belluz, & Irfan, 2018).
The way in which this process is utilised by scientists for genetic modification is that scientists realised they can “’fool’ the Cas9 protein by feeding it artificial RNA” (Plumer, Barclay, Belluz, & Irfan, 2018).
There are two parts to the CRISPR when used for gene editing, the Cas9 enzyme which cuts the DNA strand at a specific site and the guide RNA (gRNA) which helps the CRISPR system to target the specific DNA site. To begin, CRISPR will look for the specific DNA site and the gRNA helps it find the specific site. The gRNA is designed so that is complementary base pairs to the specific DNA site that is being cut out which also allows the CRISPR system to bind o the site. Once the site has been located Cas9 snips the DNA leaving a gap in the DNA sequence. Scientists then add new genes to the DNA by using a DNA donor template which designed by scientists as short, linear DNA sequences to tell the cell how to repair the gap (Ross, 2019).
Gene Drive
Gene drive is a technique that allows humans to alter the genetic makeup of an organism to have a more desired trait in the organism. This is done by changing the DNA of some of the organisms that can then spread this modification throughout the entire population species. The purpose of gene Drive is to benefit humanity in ways such as using them in insects that carry diseases or by aiding species that are threatened. However, (The Royal Society , n.d.) says that it is not yet “possible at this stage to know whether the benefits outweigh the risks.”. There is constant research being done so that the uncertainties can be reduced.
Gene drive works by either “increase the persistence of an introduced trait that would otherwise disappear from a population very rapidly because the introduced trait puts the organism at a disadvantage.” (The Royal Society , n.d.) or by spreading a desired trait throughout a population. Gene drives use the CRISPR/Cas9 technology to help increase the probability of the new trait being inherited. They use directed repair gene editing.
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