Introduction
A gene is the basic unit of heredityand contributes to the individual’s unique characteristics. Human beings possess two pairs thatare inherited from the father and mother. The transition which happens from the parents to the offspring is critical in determining the structural formation of the child. Although there exists a distinction in thegenome, it is believed that genes are similar. However, a small portion of the component called allele, contribute to the differences that aretypically witnessed in the human race. According to Martin et al. (67), genes are composed of DNA with different bases. Over the years, scientistshave tried to modify the genetic materials to come up with a more functional and improved characteristic organism. The reorganizing of the actual shape and structure of thenucleic materialis regarded as editing.
Editing involves procedures that are conducted separately to achieve the anticipated characteristics. They are classifiedasinsertion, deletion or replacement. In all the three groups, the DNA material is interfered with and replaced with desirable traits (Yu et al. 729). Currently, technologies such asRegulatory Interspaced Short Palindromic Repeats (CRISPR)have been developed to assist in themodification of the genes. The rapid appreciation in various arenas like agricultural sectors, medicine, biotechnology and research has raised concerns fromdifferent organizations such as World Health Organization. According to the study conducted by Dzau (411), it was noted that third world nations are the targets for the new era of genetically modified goods. Heelucidates that the newly developed products are tested in the developing countries, placing the lives of thepopulace into danger.Preliminary studies indicate that the effects of genetic modification are more detrimental to people than what the scientists theorize (Ellstrand 128).
Modification technologies are helpful in research work since they assist in coming up with more efficient pharmaceutical products for thetreatment of chronic diseases. However, the controversy and point of disagreement arise when the same methods are used for theproduction of crops and other consumables. Genetically modified foods havelong faced resistance in the developed countries markets, because of their association with fatal diseases such as cancer (Valdmanis and Mark361). Due to concerted efforts to impede any introduction of such products to public consumption,scientistshave transitioned their focus to use the technology in theproduction of pesticides. Though the effects of the improvements do not impact the human beings directly, they still consume the plant’s products that are sprayedwith chemicals. People are not safe by any means, as long as the gene modification continues to be employed in theagricultural sector. However, its importance is well recognized in research work and manufacturing of drugs (Dzau 412). The figure below shows the working mechanism of Cas9 nulcease, which is responsible for editing in CRISPR technology
Figure 1: The structure and mechanism of nuclease Cas9(Song et al. 76)
Technologies of Gene Editing
Gene editing has been historically defined as the addition of genes to human or plant cells. However, the new advent of genome manipulation has contributed to a new paradigm, where the technologies are used for therapeutic effects. Theseinclude correction of mutation, theaddition of genes that are more resistant to disease and removal of gene sequence (Yu et al. 730). One of the most recent techniques that has found use in hospitals and research institutions is Clustered Regulatory Interspaced Short Palindromic Repeats (CRISPR). It has become more helpful in thestudy of human diseases and formulating the drugs that target particular sites, thus, increasingly applied in thetreatment of human disorders such as Barth Syndrome (Liu et al. 27).
While technologies for gene editing have been there for adecade, using them appropriately has been the principal hurdle. Initially, researchers could introduce the changes randomly, without understanding the genome of anorganism (Martin et al. 68). The effects were more harmful, hence heighteningthe chances of risks. Unpredictability, increased errors and lack of information on how and where to execute the edition process, necessitated a group of scholars to come up with a protein (TALENs) that could allow seamless gene editing. Also, advances in sequencing means the DNA characteristics of an organism can be assembledquickly. The following paragraphs will discuss the various tools that are used in themanipulation of genes.
One of the technologies is Zinc Finger Nucleases (ZFNs), which functions in the crystal form of Zif268. It has served as the basis for understanding the working of DNA, both in plants and animal cells. The protein domain forms a compact and robust ββα structure with alpha-helical fingers wrapping around the nucleic material (Maeder 446). The structure binds the extended target sequences, improving the efficiency of manipulation (Maeder 430). Zinc finger proteins are believed to modify novel gene structures, with the desired qualities, because they can compact the strands and lower the chances of error. The advancement of ZFNs technology was made possible after therealization that nucleic acid binding domain function independently with aFokl restriction endonuclease (Martin 68). The scientists affirmed that replacing the Fokl-DNA domain with Zinc finger protein would increase the specificity. Based on the fact that Foklnuclease is a dimer, two zinc fingers would be needed on the opposite sides of the DNA strands (Valdmanis 369). The technique has successfully been employedin altering the human somatic.
Figure 2: Zinc finger protein (Maeder and Charles 433)
The second method is TALENs, which stand for transcription activator-like effector nucleases. The TALE proteins originate from theXanthomonas, a plant pathogen (Ellstrand 132). The researchers found that itfunctions in modular designs that present the DNA with excellent binding sites. The protein consists of 33-35 amino acids that enable TALE to bindto strands forming a two-helix structure. The repeats can be conjoined to create a long structure with specific binding sites (De Groot 575). The technology is attractive because of the ease to engineer new proteins and unlimited target points. However, one of its hurdles is repetitive nature of TALE protein, thus, complicated to deliver in vivo (Yu et al. 730)
Figure 3: Transcription activator-like effector nucleases (Maeder and Charles 433).
Additionally, Clustered Regulatory Interspaced Short Palindromic Repeats (CRISPR) can be used to make the desired modification (Ishino et al. 24). The research conducted by Dzau (412) identified that bacteria possess an immune system, which enables them to resist against the invading DNA virus and cut it off. Upon realization of this mechanism, the technique was utilized resize genome sections. Further modifications were done so that, the DNA was blocked instead of cutting off. More studies were conducted(DeGroot 577),and it was realized that the blocking enzyme could be reactivated using chemical triggers (De Groot 577). In the year 2016, the scholars improved the process in such a manner that it was possible to edit a single letter in the DNA strand (Yu et al. 735). DeGroot (578) opines that Cas9 is an associated enzyme that facilitates the cutting of nucleic acid strands. The endonucleases precisely target a specific section, which is eliminated and replaced by the preferred genes that induce the expression of unique traits. Unlike the other technologies, such asZFN, CRISPR allows editing of multiple sites. Also, it is more affordable and provides high-quality output. The table below shows the popularity of gene editing (Martin et al. 78).
The use of CRISPR is by far one of the most impressive inventions in the world. Based on its ability to facilitate the modification of the genes without necessarily inserting new ones, the technology has been helpful in creation of artificial seeds such as sorghum and rice. Augustine (158) comments that, “this kind of seeds has adverse effects to the users, because they are not classified as transgenic.”Based on his argument, he affirms that the seed escape the regulations that apply to genetically modified foods. The products undergo less quality checks that place the lives of the people at risk. Sequencing has been linked to introduction of toxins that increases the chances of contracting fatal diseases. However, some of the progresses have been made in editing the genome of mosquitoes that carry malaria parasite, rendering them unable to spread the disease. Based on the statistics released by World Health Organization, malaria is a threat to human existences. The survey conducted in ninety three developing countries, identified that the disease accounted for 40% of the deaths. CRSPR, would therefore, largely mitigate the deaths and prolong the lifespan (Ahmal et al. 78). According to the survey conducted by Martin et al. (76) he identified that genetically modified pigs could be used to grow organs that can be implanted on human beings. He asserts that, “People are losing lives due to rejection of transplanted organs.” One way to eradicate this case is to use the pigs, as the tool to grow certain organs such as kidney. Since the new organs contain both pig and human cells, they are referred to as chimeras.This could reduce the number of deaths caused by lack of human organs.
Figure 4: Popularity of gene editing (Martin et al.78)
The figure above indicates that from the year 2007 to 2011, CRISPR method was not used in gene editing. ZFN was the dominant technology but later overtaken by CRISPR, since its introduction in the year 2012. The speed of acquisition of this new technology is attributedto the continued improvements of research in the sphere of science.
Gene editing on embryo and Effects on Human Evolution
Scientists have discovered several methods that can be used to alter the original genetic makeup of the DNA. As the time progress, more knowledge on thehuman body isdiscovered, which has necessitated several trials in the quest to solve challenges facing humanity. Irrespective of eyebrows raised concerning the proliferation of DNA abstractions, researchers continue to defend themselves towards the move to interfere with natural makeup of an individual. Advances in genome editing have provided inexpensive ways to delete, insert or cut the DNA strands. According to the argument placed by Dzau (412), he affirms that the procedures of altering the sequencing are helpful to correct devastating defects, such as sickle cell anemia.
Modification of genes is not only helpful in ascientificfield but has some lucrative commercial returns. It can be used to design babies with specific characteristics such as heightened intelligence and exaggerated beauties. Liu et al. (28)note that the effects are detrimental to the recipient, who in this case, is the baby. The child can developcomplications and survive on medication for the entirety of their lives. Martin et al. (70) indicate that reproductive DNA is replicated from one generation to the other. Artificial introduction of such components is, therefore, harmful to the infant, who might become infertile in the future. Also, the offspring could miss specific characteristics which are passed on by parents due to errors in editing.
Application of any technology to interfere with the embryo is unethical and is highly discouraged by the World Health Organization. The process could harm the parent, the infant or both. The research conducted by Valdmanis and Mark (368) confirmed that most of theediting procedures are not one hundred percent efficient. Challenges of sequencing the actual genome of the embryo result in thedevelopment of contrary cells. When the child is born, he or she can possess some deformations either mentally or physically. According to Yu et al. (730), such cases have been reported in third world countries, where trials have failed. The observations form the primary reason the technologies are facing resistance and lack of support from health offering facilities. If gene editing is embraced in the society, it could result in thedemise of human evolution.
The ethical question that should be considered is whether the modification of genes is done for corrective purpose or to create super species? There is a complete divide regarding the ethicality of gene enhancement (Martin et al. (75). People are in support of modifications of somatic cells, but they have no idea of the consequences it can bring. Anything that alters the typical structure of a human being should be evaluated, to understand the repercussions. The technologies offer prospects for treatment of debilitating disorders such as cancer. The evolvement of new techniques to alter DNA raises thespecter, on the future of thehuman population.The technology is only effectual and helpful in drug invention, but extending it to design babies is the genesis of future generation extinction.
Organismal dynamics indicates that human beings are controllers of the process of evolution (Martin et al. 76). Studies have been conducted linking modifications of human genes to future risks of hereditary disease (Ellstrand 132). Any disruptive procedure attracts social, political and ethical commentaries from different groups. However, Valdmanis and Mark (367) are of the view that the method is helpful in eradicating some of the complex diseases that halt the performance of people. It provides a plethora of opportunities to discover various illnesses and also formulate appropriate medicine to heal them. The assertion by Dzau (411) illustrated that modifications of the embryo couldbe conducted, to alleviate abnormal conditions that could have been identified through imaging. Martin et al. (79) support the idea of disruptive procedures since they shed insight on thepossible solutions regarding diseases. According to the information from the authors who have argued for the case, genetic editing will improve evolution (Liu et al. 30). Theycite supportive ideas such asreduction in terminaldiseases and invention of modern human drugs
Gene modification in the Agricultural Sector
The world population is increasing as the time progress. According to the survey conducted by Adenle (83), he indicated that the surge of human beings in the world is imparting more pressure on the available resources. Again, according to the law of demand and supply, an increase in demand results to a reduction in supply. To solve the current menace of food shortage, scientistshave proposed mechanisms to improve the crop yields. Traditional techniques of farming have been associated with challenges of low productions and unreliable harvests. Gene editing has found anavenue in crop production, where the plants DNA are altered to come up with more resistance traits (Mark and Chris 124). This is the preface of the genetically modified plants that can thrive in adverse conditions and also overcome diseases. The new technology could be the solution to the ever-increasing challenges of hunger in some of the countries such as third world nations (Adenle 94).
Different countries have varied perception towards the modification of genomes, to produce more efficient crops. The adoption of biotechnology is widely spread in China and India. The two countries are densely populated, thus, increasing the demand for food (De Groote 564). The only solution that has been forwarded by scientists and respective governmental organizations in this country is to embrace modified foods. There are a few GMO products in North America, and arguably, the state has the best research and development endowment. Genetic modification is disregarded in Europe which has contributed to scanty adoption. The study conducted by Ellstrand (130) indicated that India, has increasingly embraced the move towards genetic engineering. The table below illustrates some of the countries and number of farmers using biotechnology (Adenle 90).
Figure 5: A graph showing adoption of gene editing in various nations (Adenle 90)
With many critics and approvals of gene modification to increase the agricultural production, De Groote (565) affirms that the new changes could be the solution to the number of deaths witnessed due to hunger. Moreover, theintroduction of particular nutrients in the crops can be used to mitigate the cases of malnutrition and the negative repercussions associated with it. Starvation statistics show that about 759 million people lack quality food to lead a healthy life (Ellstrand 130). A vast number was cited to originate from the developing nations, where 12.9% of thepopulation is undernourished. Furthermore, Asia is the most affected country, due to its high population. The research further notes that 45% of deaths were registered among the young children because they lacked enough and right nutrients to build their immunity. Based on the observation, coming up with crops that are more resistant to diseases and can grow fast would help in reducing low production. Additionally, theintroduction of the right elements such as Calcium, Zinc,and others in the crops would solve the challenges of malnutrition. Adenle (94) argues that the new technology will increase the productivity of human beings. People will become more healthy, and fight some diseases that threaten their existence. The table below illustrates application of CRISPR system in plants.
Table1: Applications of CRISPR in plants (Song et al. 79)
However, other commentators argue that the entire idea of gene modification could be the cause of human extinction. Some countries such as Europe have negative perception towards biotechnology. Gene editing in crops increases the use of chemicals. The plants are, therefore, grown under an environment that embraces the increased use of herbicide and pesticides (Ellstrand 130). The consequences are detrimental to the lives of people. For example, prolonged use of chemicals leave some traces on seeds or fruits. The toxins are transferred to human body through consumption, hence, start developing complications that threaten their lives. Similarly, insertion of selected traits imported from other crops might result in unpredictable effects. Mixing genes from varied species lead to thedevelopment of allergens. Independent research conducted by De Groote (570) affirmed that continued reliance on gene editing is a significant threat to human life.
Genetic modification in Medicine and Impacts on Human Evolution
The health sector has faced many challenges due to the influx of people diagnosed with chronic diseases. The situation has increased workloads on the available professionals, resulting in the reduced quality services. Camarasa (140) argues that the ever-growing number of patients in both public and private hospitals is contributed by lack of appropriate medications. Continued reliance on the traditional medicines has caused mutations of bacteria, thus difficult to eradicate the devastating conditions. Notably, the current situation regarding the increase of incurable illnessesemanates from the continued usage of the same drug for a long time. The resultant impact is the development ofstrains of bacteria that are difficult to eradicate with the same mode of action (Edeline 336). Similarly, cancer and diabetes have traumatized many people. With the introduction of CRISPR, it is now possible to eliminate life-threatening conditions at an early stage. The figure below illustrates gene editing procedure.
Figure 5: Repair consequences of targeted DNA cleavage (Song et al. 80)
Clustered Regulatory Interspaced Short Palindromic Repeats (CRISPR) is a new technique that can be used by clinicians and other medical practitioners to study various genetic diseases (Mark and Chris 58). In the recent study conducted by Weyrich (234), it was noted that certain conditionscouldbe halted by changing the sequencing of genes. Based on the mode of action of this technique, the Cas9 nuclease is used to cut off a particular section of the DNA. It is replaced with the desired properties that render the human beings more functional and healthy. The information released by Edeline (337) opines that diabetic traits couldbe stalled by editing the section of the gene that causes the disease. It is achieved by decreasing deaths of beta cells, and consequently increasing insulin production. More fatal ailments such as sickle-cell anemia can be treated through the same way. The consequences of gene editing have been linked to improving the innovations in the medical field, with more changes happening in the sector. Irrespective of criticism placed against its use in the agriculture, researchers believe that it could result in prolongation of human life (Weyrich 245).
As with other medical and research advancement, the use of gene editing technologies raises concern in the society. The sudden explosion of CRISPR has attracted various bodies such as World Health Organization and various governments, to prompt the efficacy of the modern methods regarding human protection. Multiple questions arise as the considerations and evaluations are conducted to ascertain the applicability of the alterations. One, is it ethical to manipulate the natural make up of a person? Two, do the techniques respect the different beliefs and cultures? The study conducted by Edeline (342) affirms that people have different perception concerning biotechnology. Based on religion, some advocate for it while other rescind the support that would destabilize their original form. Due to this fact, some countries such as Europe hold a different perspective from what a county like China does (embraces gene editing).
The safety and efficacy of the current techniques are well understood by the different stakeholders involved in medical platforms and research work. The new understanding and progressivestudieshave made it easy to edit the gene, with much preciseness. The scope has enlarged the landscape of innovation, and the principal concern is how the society will accept the technology (Weyrich 252). The challenges are layered on scientific,ethical issues, which causes disagreement between the various governments and the experts willing to offer the services. More efforts are required to advocate for gene editing. Based on the observations identified by different researchers, more benefits are associated with modification because the span of living is extended, through the elimination of diseases (Camarasa 141). Increased use of therapeutic CRISPR is a sign of its future adoption.
Some of the Gene Therapy Applications in the Medical field
Some human complications that have been threatening their existence can now be treatedby deleting or blocking the DNA strands. The advancement is the replacement of the traditional imaging technologies that have been for use for long. X-ray, CT scan and other methods have been in hospital applications, but the numbers of deaths due to cancerous cells are innumerable. According to (Camarasa 140), cancer is among the leading cause of morbidity and mortality. About 8.8 million people in the world died in the previous year, as a result of succumbing to chemotherapies and prolonged use of supportive drugs.
One area of application is the cancer immunotherapy, which is among the advances in the biomedical field. To be specific, T-cell immunotherapy involves designing autologous cells that can attack the cancer cells (Weyrich 250). The modification is done by introducing the right antibodies that can fight the disease. The technique can be potentially improved by gene editing. It would involve entering chimeric antigen receptors that can detect the cancerous cells at early stages. Moreover, respiratory disorders are caused by the mutation in the chloride channel. Blocking its function results in the loss of fluids, leading to thickening of mucus around the lungs. Such a condition is characterized by theunconditioned flow of fluids, which makes it hard for an individual to breathe. Recent advancement in the study of human diseases has shown that the mutations of CFTR can be avoided by gene editing.
Furthermore, skin diseases can also be treated through gene modification. There are conditions that are caused by the immediate environment, while others are genetically inherited. Treating topical ailments is easy because there are an array of lotions and creams that are applied to lessen or clear the severity of the problem. However, diseases that are propagated from the parents would require a sophisticated process, of editing the genes, by inserting a more desirable one. Grafting a skin from allogeneic cells is creating an opportunity to treat external problems related to the gene(Edeline 337).
Conclusion
Gene editing could be the solution to the unsafe human conditions. The gradual appreciation of technologies in the field of medicine gives hope to the future of more effective drugs and improved ethos to deal with chronic diseases such cancer, diabetes and other. Additionally, it is used in the agricultural sector, to come up with crops that are: resistant to diseases, grow fast, contains high nutrient value and possess specific characteristics desirable to the farmer. The sudden discovery of GMO crops raised the concern of various organizations, who questioned the safety of the plants. Due to this facts, some of the countries such as Europe have aminimal appreciation of biotechnology. However, countries such as India and China have no limitation for the genetic modifications in agriculture.
Although there are risks associated with gene modification, the reviewed studies have revealed that human beings stand a chance to benefit tremendously. Instead of continually relying on old treatment methods, which are less efficient, introducing resistive gene could help prolong the life. Moreover, engineered crops would assist in eradicating hunger, which has claimed the lives of many people, especially in the developing nations. The stakeholders and research institutes should work together, to agree on some ethical standards that should be followed when performing the procedures.
Instead of campaigning against the idea of gene editing, it’s essential to seek to understand the practical implications. Various governments should fund research projects, with an objective of benefiting the populace from the modern advancements. Additionally, the scientists have a responsibility of conductingthe manipulation techniques ethically. The major cause of disconnect between the society and impressive discoveries is lack of knowledge. Some people oppose ideas based on unfounded truths. To bridge the gap, experts should create awareness to the public concerning the effects of gene editing. If efforts are directed towards eradication of human challenges, sequencing promises advancement of human evolution.
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