Regions of DNA for Diagnostics or Forensic Purposes - Essay Example

?Proposal for an Experimental Design to Detect Regions of DNA for Diagnostics or Forensic Purposes Introduction DNA (deoxyribonucleic acid) is a representative of the blueprint of the makeup of human genetics. It virtually exists in every cell of the human body and is distinct in the sequence of nucleotides making up DNA. The genome of human is made up of 3 billion nucleotides. These nucleotides are 99.9% identical from every person. Evidently, the 0.1% variation can be used to differentiate one individual from the other. This difference can be used by forensic scientists to match blood and tissue specimens or hair follicles to individuals with a very high level of certainty. This is what has taken my interest in choosing this molecular target. This paper, hence, seeks to produce a proposal for an experimental design to detect regions of DNA for diagnostics or forensic purposes. It is important to make certain that a complete DNA of every individual is unique, except for identical twins (Stephens, 2006). Therefore, a DNA fingerprint, also known as DNA typing, is a DNA pattern with a unique sequence so that it can be differentiated from the patterns of other individuals. Thus, my molecular target is the DNA fingerprint. Identification of the Named Target (DNA Fingerprint) DNA fingerprinting is based on analysed DNA from the genome regions that separate genes referred to as introns (regions inside a gene which are not part of the protein encoded by the gene). Introns are spliced out during RNA messenger processing, an intermediate molecule allowing DNA to encode protein. This is particularly different to the analysis of DNA for mutations that cause disease. This is because most of the mutations entail the gene regions (exons) that encode protein. In the identification of this named target (DNA fingerprint), we can also assert that DNA fingerprinting often involves introns since exons are mainly conserved and have much less variability in their pattern and sequence (Pena, 2000). Originally, DNA fingerprinting was used for identification of genetic diseases via linking the genes of a disease within a given family with the basis of inheritance of the markers and the possibility that segregating markers would be in close proximity. However, DNA fingerprinting can also be used for forensic science and criminal investigations. The courts in the United States also accept the reliability of DNA analysis (Rider, 2007). However, the cost of testing, the accuracy of the results, and the misapplication of the technique have resulted in many controversial concerns with the technique, hence the basis of this study. Steps Required for a Suitable Experiment from Sample Collection through to Data Analysis In forensic laboratories, various steps are followed in the analysis of DNA for various reasons. After collecting human samples such as semen, blood, urine, saliva, tissues, hair, bones, or buccal (cheek cells), DNA is extracted from the samples and analysis is carried out in a forensic laboratory. The results from the DNA analysis are then compared to the actual DNA analysis from the identified (known) samples. The DNA that was extracted from the samples collected from a scene of crime can then be compared and matched possibly with the samples of DNA extracted from the suspect or victim (Landis, 2008b). During extraction of DNA from a cell, it may be done from two different sources. DNA can be extracted from the cell nucleus which contains information making individual human beings who they really are. The other source may be cell organelles known as the mitochondrion that produces energy driving all the processes of the cell necessary for life. Nuclear DNA is often analysed within evidence including semen, blood, body tissues, saliva, and hair follicles. On the other hand, DNA extracted from the mitochondrion is often analysed with evidence consisting of bones, hair fragments, and teeth. It is also important that where there is an inadequate amount of sample, preference be given to mitochondrial DNA analysis (Landis, 2008a). Once the extraction of DNA is complete, it is then analysed with molecular genetics techniques. In case there is inadequate DNA to evaluate directly, the polymerase chain reaction technique is used in order to amplify the DNA genome from the selected sample. This procedure will allow us to amplify exponentially a specific DNA sequence in the genome in order to make it large for analysis. The analysis of DNA will then be performed through sequencing the DNA fragment that is amplified, using the nucleotides that are labeled fluorescently and a laser that recognises nucleotide based on the fluorescently labeled nucleotide where it is attached (Mourice 2008). However, the technique may be expensive and, hence, may amount to limitation of the study. On the other hand, if there is enough DNA extracted, such extracted DNA from the sample is segmented or cut using particular enzymes, proteins speeding up the chemical reactions, referred to as endonucleases which act as the molecular scissors through cutting particular enzymes recognised by them. Through cutting in a similar sequence present in distinct locations in the genome, fragment patterns may be performed (Heiser, 2007). The differences in the patterns of the sequence between the samples may be because of variations inherited in DNA distinguishing the samples. After cutting DNA, the segments will be arranged using the electrophoresis process by size. In this process, an electrical field is then generated, which pulls the negatively charged DNA towards the DNA which is positively charged through a gel-like matrix. The segments marked with probes of radioactivity are then exposed on a film of X-ray in which they form a pattern of characteristics of black bars. This pattern is what is referred to as a DNA fingerprint. If the DNA fingerprints from the samples match, then the samples are most likely from the same individual (Dom, 2009). Information about Controls and Replicates In summary, we can assert from the study that any type of organism can be identified through examination of the sequences of DNA which is unique to that species. Identification of individuals within a specific species is much less precise, even though when technologies of DNA sequencing progress further, direct comparison of the whole genome or very large DNA segments will become practical and feasible, and this will allow accurate individual identification. In order to identify individual species, forensic scientists can scan 13 DNA loci, or regions, which vary in individuals and create a DNA profile, using the data of that individual (Terry, 2000). This is accurate in most cases because there is extremely little chance that one person has the same DNA profile as another one for a specific set of 13 regions. References Dom. G., 2009. Molecular chemistry. Journal of Coordination Chemistry, 62 (1), pp. 108–109. Heiser, D., 2007. DNA sequencing. Ann Surg., 192 (1), pp. 44–52. Landis, S., 2008a. DNA fingerprinting. Journal of DNA Patterns, 6, p. 30. Landis, S., 2008b. DNA technologies. Manchester: McGraw-Hill. Mourice, K., 2008. DNA technologies. London: Prentice Hall. Pena, S. D., 2000. DNA fingerprinting: state of the science. Liverpool: Birkhauser. Ricks. E., 2007. DNA typing. Southampton: Pearson. Rider, W. D., 2007. DNA sequencing and patterns. London: SAGE. Stephens, J., 2006. DNA fingerprinting analysis detecting a community-based tuberculosis outbreak among HIV-infected persons. London: John Wiley and Sons. Terry, M., 2000. DNA fingerprinting: approaches and applications. London: SAGE. Read More