Clustered Regularly Interspaced Palindromic Repeats - Essay Example

CLUSTERED REGULARLY INTERSPACED PALINDROMIC REPEATS No Lecturer) Clustered Regularly Interspaced ShortPalindromic Repeats also referred to as CRISPRs are sequences in a gene locus. They contain short base sequences repeats. These sequences were first realised in the 1980’s particularly in the prokaryotes. It has been projected that spacers separate these repeats. Spacer elements are suggested to have occurred due to past exposure of bacteriophages or any other extra-chromosomal DNA. CRISPRs structures are often associated with a cluster of genes called CAS genes. These genes have been isolated from many bacterial species such as Streptococcus SPP. Extensive studies carried out on bacterial cells have shown that bacteria has a high tendency to incorporate foreign DNA into its genome. These structures have therefore been hypothesized that together with the CAS proteins contribute to the cells’ immunity against bacteriophages and also from expressing foreign DNA. Bacteria are known to use different methods of defence mechanisms against viral attack. These include masking of surface receptors where the bacteriophage attaches, use of restriction enzymes that cleave the invading DNA and now recently the use of CRISPs/cas9 complex. This relatively newly discovered system is a form of adaptive immune system with a capability to remember past attacks by prophage, phage or plasmid. It enables the bacteria to remember the invading pathogens preventing the second and subsequent infection. CRISPRs/cas9 complex is associated with a small non-coding RNA that cuts the invading DNA and hence destroying. The mechanism involves first incorporating short sequences from the foreign DNA known as spacers into the repeating units. These units are then transcribed into short RNAs (crRNAs) by CAS genes. Finally, this complex initiates the cleaving of the invading foreign DNA. Technology has improved greatly over the last with scientists mapping the whole human genome that consist over 3 billion base sequences. An overwhelming revolution in the genetic engineering has mesmerized scientists to what level technology has risen. The gene mapping technology has been tried in the past with no apparent breakthrough. This is because these trials are very risky especially when it involves changing particular genes and the ultimate manipulation of these genes. Regular discovery of the clustered interspaced short palindromic repeats which has heavily impacted on the scientific world. At first these systems were hypothesized not to partake in any cellular functions in the bacterial cells and also to the eukaryotic cells. Continued studies, however proved this wrong when it was discovered that these systems were involved in the defence mechanisms, in the bacteria. As years progressed, these systems were almost rendered useless in relation to human genomic studies until a few years ago. Recent studies have shown that CRISPRs/cas systems are the new rising stars in genetic editing. This technique involves the identification of mutated genes, cutting them out finally replacing them with new correct DNA fragments. This is a context earlier thought to be part of science fiction, but its’ been successfully transformed into reality. It has found great importance in the treatment of genetically associated diseases and even eradicating completely these diseases. Earlier tools of genetic editing techniques are Zinc finger nucleases (ZFNs) and Transcription activator-like effector nucleases. CRISPRis the most recent technique and uses enzyme cas9 to edit out desire portions of the eukaryotic organisms genome. These are easy to use and manipulate and can be easily programmed to act on multiple regions of the genome at once. They are also projected to have a very high accuracy and minimal errors in cleaving out parts of DNA that are undesirable. Processes of DNA sequencing technology have grown tremendously. This does not exclude the fact that most deadly diseases are still thriving among us. Disease such as sickle cell anaemia which is as a result of mutation on one gene continues to pose a life threatening risk globally. This is so despite the fact that genetic engineering has been at play for several decades. With new technology and the use of CRISPRs/cas9 systems, permanent solutions to such genetic defects are on the verge of being solved. Many scientists have been excited by these structures and a great deal of research is on the progress. Numerous trials have been done using laboratory animals especially mice and rats. Experiments have been done using the enzyme cas9 create knockout mice. This generates double strand breaks which could be lethal with the subsequent DNA repair through non-homologous end joining. Diverse applications of CRISPR-cas9 are being realised with each day as scientists embark on intensive research. These include methods of silencing the genes, and turning off and on of genes. Although there is a great success in this technology, scientists have noted that there are challenges too. The biggest challenge in this methods is specificity. It has been reported that the cas9 enzyme can cleave the DNA in areas that are not intended in the genome. This is because cas9 enzyme has low selection ability. Researchers are able to use this technology to disrupt genes and thus able to design new drug targets. It has also helped in the knowing of processes or stem cell programming and hence the regeneration of organs such as liver and also in the cure of AIDs. Technology of gene therapy has been widely applied in agriculture. This has been used to produce genetically modified crops and livestock. These procedures have led to high yielding of produce exhibited by both plants and animals. Introduction of CRISPRs systems to crop production presents a highly potential field. Being powerful and very accurate, this technology could take the agricultural sector on a whole new level. The technology can be used to shorten the life cycle of the crop. Experiments carried out on certain species of rice shows that the application of CRISPR/cas system can be used to manipulate the genes, therefore, shortening its life cycle and also improving quality and quantity of the yield. Positive results on that experiment will trigger interest to research on higher crops such as maize with higher genomic size. Individuals have come up with ideas to create research facilities dealing specifically with genetics and genomic manipulations. Editas medicine is a company that has been donated $43 million. Its main aim is to use CRISPR/cas system to treat genetically associated disorders such as sickle cell anaemia, Huntington disease and others. This company will work together with research facilities to achieve these goals. Its’ an indication that research in genetic engineering have gained interest on individuals and they are willing to ensure quality health care is provided. This is prospected to feature positively on the global healthcare in the future. Biological perspective of this new technology, however, might be different and present some contradictory instances in the society. The biological ethics in this context reflects on both the embrace of this new technology taking into account the morals of the society. Various groups of people have viewed the use of technology in very diverse ways. While one group proposes adoption and incorporation of the great opportunity to eradicate genetically associated diseases, another group opposes that line of thought. Since every individual in the society is entitled to their own independent opinions and choices, the debate about the ethical values of using this technology to engineer genetically and manipulate the human genome is still on the table. Both sides present viable reasons and convictions as to why their line of thought should be adopted. Some experiments conducted by geneticists, however, did not achieve appraisal as they were seen as inhumane. These experiments associated with the human-animal hybrid produced the chimeras. In many countries, this crossbreeding between species has been banned. One concern about this technology is in the case of correcting mutations in the human embryos. CRISPRs systems can make this happen. These mutations on the germ cells carried out in vitro fertilization may alter genetic makeup of the following generations. This procedure can be tempting to families with a history of specific hereditary lethal disease. Effects of such procedures are not yet known and they might have long lasting effects on the foetus (Judith Reeks 2013). Also, it is a right to every human to make their own choices. By allowing this procedure, the foetus or the unborn child is deprived off these rights. Also, this technology could lead to making of the designer babies which is unethical. The human genome project in many countries has been made illegal and should not be practised. Also, the respective governments have denied funds to such projects. According to the animal rights activists, animals should not be used as laboratory animals. Animal Welfare Act (Laboratory Animal Welfare Act of 1966), laws have been enacted to control the animal rights and their handling. The provisions of the act only permit certain species of animals to be used for research. Many other groups that advocate for animal’s rights are on the rise. This is to ensure that biomedical ethics is not by-passed by the researchers leading to mishandling of the animals. Use of painless methods in the lab has been highly advocated for. High and revolutionised technology is not enough. Animal models are required to test these speculations and hypotheses. These animals are subjected to diseases and then clinical trials are done. Use of CRISPRs systems technology to effect mutation usually has negative effects on the test animals. Due to ease of creating lab animals using this method, there has been high risk that more animals will be used in these experiments thus raising an eyebrow (Anita Marchfelder 2012). Genetic engineering is an overwhelming field in the study of gene therapy. As far as this technology can be used for repair of mutated genes leading to lethal and life threatening conditions, a relatively high number of individuals will be tempted to use it for enhancement. This means that people will want to enhance themselves by altering their genome to become superior. Due to CRISPRs/cas9 ability to transform the genome, there is a high chance that people will use this method to improve their genetic makeup. This will raise concern as the method should be used for medical use only (Geoffrey M. Gadd 2012). There will be a tendency of deviation from medicine to the field of eugenics. Also, the therapeutic potential of this technology involving microsurgery of the gene has not yet been proven. Assessment of safety of these procedures has to be done to be assured. Some people will argue there is no problem in using the CRISPRs/cas9 technology in treating defective genes in the germline therapy. The ethical perspective is that instead of using techniques such as Pre-implantation genetic diagnosis (PGD) the germline therapy should be used. This happens because PGD involves the selection of an embryo without the defective genes. This method leads to termination of the embryos with the defective gene. Contrary to that, the germline therapy provides a chance to the life, it focuses on the treatment and cure which is permanent as compared to the PGD which would lead to the selection. This technique is also relatively easy to carry out and its accuracy is higher. Use of this technology is paramount to human health. Scientists have carried out experiments that have cured cystic fibrosis. Also, the treatment of sickle cell anaemia has been successful in the laboratory. Through stem cell regeneration technology, certain defects such as leukemia have been treated. However, the technology might pose a risk to health, an individual suffering to these genetic defects can be more than ready to try these trials. Medical breakthrough in the field of medicine in managing these defects will have to involve human trials. It may be hard to convince a person who is already suffering from these defects not to take the risk in trying the technology. Even if this project of altering the human genome is illegal, somehow people are still managing to carry out these processes. It is, therefore, evident that ethical issues are addressed from an individual’s point of view. Companies in the agricultural sector use this technology to alter the genes of crops. This transiently leads to mutation of the genomic makeup of the crop. Foreign DNA can be introduced and mixed with the crops DNA and this can lead to the production of new traits for the same crop. These changes could be contrary to the regulations of genetically modified crops (Jore 2010). Discussions about genetically modified food has been found debatable with arguments that its’ safe to consume such food while other parties strongly believe that its’ unsafe. This raises ethical concerns in the society. However, most of these changes are beneficial but also can lead to the production of harmful substances such as toxins from the crop. CRISPRs/cas9 technique of knocking out mutated parts of the DNA and replacing with the correct sequence have been conducted. However, these structures have also been shown to effect off targets (Judith Reeks 2013). Mainly this occurs at regions similar to the target region. If this occurs, the effects could be lethal than the condition which was being corrected. The fact that these trials might not be positive, there is a great danger involving such procedures. This has raised significant ethical concerns and the debate issue is still being debated on. Scientists are working out ways of increasing the specificity of these systems to minimize such conditions. Following the current trends in technology, more innovative ways are being introduced into the field of genetic engineering and medicine at large. The regular use of clustered has been interspaced in short palindromic sequences in the genetic editing is one of the way in which lives are being transformed. Cure to genetic disorders and incurable diseases such as sickle cell anaemia, Down syndrome, cancer, Huntington disease is almost realised. This new technique is easy to use and simple when editing a desired part of the gene. Over the past years, gene therapy largely depended on methods that are inaccurate. DNA insertion occurred purely by chance, this could happen anywhere on the genome. This has greatly been transformed due to the introduction of CRISPs/cas9 technology. There are high hopes that great medical achievements will be realised (Geoffrey M. Gadd 2012). Conclusion Bioethics and the numerous controversies facing this new technology will sooner or later be dealt with. The acceptance of change in the society is a fundamental central feature that dictates the rate of growth in social, economic welfare. Adoption of CRISPRs/cas9 system in the treatment of genetic defects is an important indicator of positive growth. However, the use of this technology must be regulated to avoid cases of mishandling the knowledge. If such technology lands in the hands of self-centred individuals, it can be used to harm the society. Public debate should be encouraged to identify the general feeling of the society. This would also help in evaluating the vast numbers of ideas flowing from the public. The legalisation of such technology to be tried clinically should not be centred to the morals of the society. This technique poses a high potential towards advancement of mankind. The technology offers great milestones towards treating diseases and towards gene therapy. References Anita Marchfelder, Wolfgang Hess. Regulatory RNAs in Prokaryotes. New York: Springer, 2012. Bruijn, Frans J. de. Handbook of Molecular Microbial Ecology II: Metagenomics in Different Habitats. London: John Wiley & Sons, 2011. 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