Gene editing & manipulation
What is gene editing?​
Gene editing is a form of genetic engineering where DNA from humans or other species of animals, insects or plants are either inserted, deleted, modified or replaced in the genome of a living organism. Unlike the original processes of early genetic engineering techniques, where a machine randomly inserts genetic material into a selected host’s genome, genetic editing specifically targets the genome where the insertions or edits take place.
What are the different types of gene editing and how do they work?
There are three different kinds of gene editing, which help target genomes and genes and change their DNA compounds in different ways. These forms of editing are Zinc-Finger Nucleases (ZFNs), Transcription Activator-Like Effector Nucleases (TALENs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas9. ZFNs are custom DNA endonucleases which recognize three to four bases of sequence in the genome, and scientists can more or less target any sequence they wish. However, the efficiency of this method is pretty low compared to the other methods as it targets three or more sequences of genome. TALENs on the other hand are made up of nucleases built from arrays of 33 to 35 amino acid modules, which target a single nucleotide in the genome of a host organism. This makes scientists target nearly any sequence they like with limited off-target effects, yet this method still has a low efficiency because there are errors in amino acid and nucleotide matching. Finally, CRISPR-Cas9 is another gene editing method where enzymes bind to DNA sequences and cut the unwanted parts out.
How has gene editing been used so far?
Gene editing has been used for over fifty years in the form of genetically edited plants, agriculture, insects, animals and even humans. Below are five profound examples of how gene editing has been used so far:
-
The first form of gene editing began in the 1960’s when scientists used radiation to create random mutations to plants, as the radiation changed the genome of the type of plant. In most cases this technique rarely produced any useful mutations.
​
​
​
​
​
​
​​
-
Another example of how gene editing has been used is the Flavr Savr tomato. This special tomato was invented in 1992 by a Californian company called Calgene. This tomato was genetically modified so it could stay fresher for longer by adding antisense genes to interrupt the production of rotting enzymes making it last for longer.​​​​​​
​
​
​
​
​
​
​
​
-
In 1998, the first genetically edited mosquito was invented. Scientists had the vision to create a genetically modified organism (GMO) that could prevent diseases from being contracted to humans. They did this by creating the genetically modified mosquito. Scientists have made some mosquitoes express a small protein called SM1, which blocks entry of the malaria parasite, dengue and zika virus into the human body. If these mosquitoes were to spread in the wild, then there would be less chance of contracting these diseases.
​
​
​
​
​
​
​
​
​
-
On the 31st of July, 2000, a Swiss scientist named Ingo Potrikus created a new genetically modified food called “golden rice”. This rise was particularly helpful because it contains provitamin A. The lack of this vitamin is especially harmful people who live in poorer countries and is estimated to cause blindness for among 250,000-500,000 children every year and another two million people a year die from other deficiency-related causes. The introduction of the golden rice has dramatically reduced these numbers
​
​
​
​
​
​
​
​
​
-
On 26th of November 2018 a Chinese scientist, named He Jiankui has claimed to have made the first genetically edited baby. The Chinese scientist did this by altering the embryos for seven couples during fertility. Ever since this scientific breakthrough the whereabouts of the scientist is unknown.
​
​
​
​
​
​
​
​
​
Why is human gene editing such an ethical, social and safety concern?
There are three main concerns with gene editing in the future, which include social, ethical and safety issues. These issues may alter the way we use the gene editing technology in the future, by limiting its use because it is unsafe and unpredictable, it has ethical issues and it may affect the social norm of our society.
​
The social issues of gene editing include, transforming the genetic make-up of humans and is the technology accessible to everyone. Once a specific human has had their genetic make-up changed then they can spread their new traits to their offspring, which will greatly change the genome of our entire human species. Satyajit Patra from the American International Medical University states that as we edit the genome of more people there will be a reduction of genetic diversity making humans having “identical genomes”. In addition, the gene editing technology may not be accessible for poorer people but will be easier for richer people to access and have themselves cured of diseases, leading to inequality. Philosopher and expert on ethics, Richard Heersmink from the La Trobe University states that poorer people will have no access to gene editing therapy, whereas rich people, who are already quite intelligent, will have great access to this technology, and if they decide to raise their IQ or enhance their physical abilities then there will be a much bigger class divide between poorer people and richer people.
​
Furthermore, the ethical concerns of genetic editing include, gene editing used for human enhancement and humans taking over the role of God. Gene editing can not only be used for curing diseases but it does have the possibility of enhancing a human’s characteristics such as intelligence and athleticism. Dr E. Rodriguez from the University of Chile explains that genetic editing can be used in a non-therapeutic manner that could lead to enhanced individuals having a massive advantage over normal humans. Moreover, in many religious beliefs people believe that it is God’s role to create life, but with the power of gene editing we are taking over God’s role. Richard Heersmink from the La Trobe University also explains that it is God’s divine role to give life and by editing people’s genes to make them different, people from different religions are becoming enraged because, “we are taking over God’s role as the creator”.
​
Additionally, the safety concerns of gene editing are possible side effects when someone’s genes have been edited and the accuracy and efficiency of this technology. Scientists have already started testing gene editing on humans and animals and some unwanted side-effects have been discovered. Genetics Home Reference indicates that multiple scientific tests have been made and there have been side-effects produced, such as toxicity, inflammation and cancer. In addition, the efficiency of this brand new technology is quite low and editing human’s genes could lead to some unwanted changes. Allan Bradley of the Wellcome Sanger Institute in the UK says that the technique can cause big deletions or rearrangements of DNA in humans. It is currently way too early to start but once we improve the technology and make it more efficient there will be less safety risks.
​
​
​
​
​
​
​
​
​
​
​
​
​
