Polymerase Chain Reaction as a Method of DNA Fingerprinting - Lab Report Example

Fingerprint Student’s Name Course Instructor Date Table of Contents 1.0Title 2 2.0. Abstract 3 3.0 Introduction 3 4.0 Aims 5 5.0 Methods 6 6.0 Results 7 7.0 Discussion 8 References 10 1.0Title PCR Based DNA Fingerprinting lab 2.0. Abstract The processes used here is for detecting the presence of matching DNA fragments from four suspects who broke into a house. After the DNA found at the scene of crime is tested, it formed a line and when the DNA tests of the suspects is performed, they are compared to the marker line which is the DNA sample from the crime scene. Which ever matches it, the suspect is guilty of the crime. It was clearly indicated that, even PCR may be a complicated method of DNA fingerprinting; it is a very effective in uncovering criminal activities. 3.0 Introduction Polymerase chain reaction (PCR) has the capability of producing large amounts of a specific piece of DNA of starting amounts from trace amounts. This is traced from a cheek cell, a drop of blood, a single air follicle, or even a peace of born to produce copies of the desired DNA fragment in their millions. It is only a small or single intact strand of template DNA through PCR is needed to produce large amounts of new DNA molecules. It would be impossible to do forensic with small amounts of DNA without PCR, due to its ability to amplify the sequence of DNA which is a prior requirement in any study. It is a point worth noting that, this methodology engages two primers; short single stranded sequences of DNA and a special high temperature stable polymerase so as to come up with a variety of copies of a sequence in a DNA sample. It clearly enables the researcher make a number of copies of a specific region of the genome from a sample and this is very vital for it enables analysis isolations (Griffiths et al 2008). When a sample is received, genomes, which vary between individuals, are amplified and the variable number tandem repeats. Then by comparing different repeats of variable number tandem, it turns out very easy to establish whether the suspect’s sample matches that under scrutiny. DNA is highly considered in forensics solely because it contains the vital genetic information within the cells of all living organisms (Griffiths et al 2008). They are considered blue prints of the human body which attests to the fact that they contain important information which is necessary to build all components of a cell such as proteins and RNA molecules. DNA sequences also provide very important information in regulation of genes (Gaensslen, Harris & Lee 2008). These gene sequences are called alleles and it is the differences they contain that are analysed in DNA study. In the same case, there is a variety of ethical dilemmas entwined with genetics which encompasses the ability to come up with new technologies thus designing of new genetic tools can not be compared with the ability of the people to evaluate these tools’ efficiency and effectiveness (Lewis 2009). Science and technology has a tendency of forging ahead irrespective of the cultural and ethical implication associated with such developments. DNA database is a collection of data obtained from DNA, informs of DNA itself or standardized representation of DNA sample, for instance DNAF. It is considered unethical to take samples and profiles of DNA without securing the relevant consent. However, in order to ensure liberty of all people, there is need to prevent them from the criminal activities in such a way that, discrimination is discriminated (Cooper & Hausman 2009). A balance between ethical considerations and privacy needs to be put in place when undertaking any DNA test. There has to be distinct justification due to the aspects that the basic ethical and legal principles which implies that an individual has a right to control access to his or her body and any other body intervention. In the criminal justice process, the samples taken from a suspect can only be processed in accordance with the consent of the person involved. This therefore means that, the data must be obtained only through acceptable procedures disregarding the unacceptable coercion or deception (Griffiths et al 2008). In addition, the disclosure of data must be undertaken in such a way that it curtails their use for purposes outside the consent given. In the same case, where DNA profiles and biological samples are used, safeguards should be put in place to ensure that anonymity of the sample is irreversible. A forensic database functioning appropriately has the potential of promoting public interest to certain levels and this being the case, the loss of personal freedom as a result of DNA samples is outweighed by the achievement in personal security and social order through effective detection and conviction of offenders. However, in all cases, it is paramount to avoid any form of compromising ethical considerations while undertaking any form of investigation. 4.0 Aims The aim of this practical is to identify which suspect left their DNA at the Scene of Crime. 5.0 Methods There were four extracted DNA from suspects (PY01, SL01, DH01 and RE01). Then there were 5 PCR tubes with reaction beads and primer mix. The PCR tubes were labelled using PY01, SL01, DH01 and RE01 and each tube was tapped to ensure that the PCR beads get to the bottom. 20µl of primer mix was added to each tube, and then 5µl from the extracted samples were added to their respective labelled tubes, then, they were mixed using a vortex and pulse spins using centrifuge so as to make sure that bead is dissolved. They were preserved in ice until all are prepared. All samples were then placed into thermal cycler and underwent a program as follows: Initial denaturation in 94⁰C for 3 minutes, 35 cycles of 94⁰C for 30 seconds, 45⁰C for 30 seconds and 72⁰C for 30 seconds and finally, Final extension in 72⁰C for 3 minutes 5 µl 10x gel loading solution was added to each tube and stored at -20⁰C for some days. 0.5g of agarose were then transferred to a 250ml flask, the mixture of 1x buffer and agarose were completely mixed and heated on high power for 1 minute so as agarose can dissolve. The agarose solution was then poured to the gel casting tray. 200bp DNA ladder and 5 PCR samples were placed in a hot block in 50⁰C for two minutes and then allowed to cool and then loaded to the gel 30 µl. The gel was then removed from the tank for staining in a cling film. A clear plastic sheet from the Instastain® card and placed on the top of the gel and pressed to get firm and allowed 10-15 minutes for staining and finally, the Instastain® card was removed and the gel viewed on a UV transillumminator. UV protective goggles are worn. 6.0 Results It is accepted that, DNA fingerprinting can be used to investigate criminal cases. Researchers only need to match the DNA of the sample collected at the scene of crime with the DNA samples taken from the suspects to determine who was guilty of the crime committed. After an attack by Robbers at The Brewery Tap, traces of blood was seen on the window frame which must have been from one of the accomplices. Paul Young was arrested and the questioning that followed led to the arrest of three more suspects. They were all asked to submit DNA sample for analysis in the form of a Buccal swab. Figure: four suspects have been accused of robbery, and DNA analysis has been performed on the blood sample found at the widow plane and the suspects. Line 1 from the right is the marker DNAs. Line 2 through 4 is samples for suspects PY01, SL01, DH01 and RE01 A respectively. Partly on the basis of this evidence, suspect PY01, was found guilty of the crime. His DNA sample match the DNA from the blood found at the scene of crime. 7.0 Discussion From the figure, it is clear that, PY01 (L2) is guilty of the crime for his DNA fragments matches those of the blood found at the scene of crime, line 1. Suspects 2, 3 and 4 are not his accomplices’ for their fragments do not match the one found at the scene of crime. DNA fingerprinting is a useful tool in such a case for it provides an exact match with the sample of whoever left the evidence collected at the scene of crime (Butler 2005). A match of the DNA of a suspect and that left at the scene of crime is a clear indication that, the suspect was the one who actually committed the crime. Under normal circumstances, the DNA of an individual can never match that of another and therefore, there can be no errors in analyzing any results. DNA fingerprinting is a reliable method that can be used to indentify living organisms (Lewis 2009). Furthermore, DNA is a unique material within an organism and it can never be altered even once it has left or deposited somewhere. PCR bases DNA finger printing is the commonly used and it uses small amounts of sample of DNA. Conclusively, DNA is a reliable method which enables researchers gets the identity of an individual correctly. References Butler J., M. 2005. Forensic DNA Typing: Biology Technology and Genetics of STR Markets. 2nd Edn. Massachusetts, USA: Elsevier Academic Publishers. pp 640 649. Gaensslen, R.E., Harris, H.A., & Lee, H. 2008. Introduction to forensic science and criminalistics. . New York: McGraw Hill. Geoffrey M. Cooper, Robert E. Hausman. 2009. The Cell: A Molecular Approach, Fifth Edition. New York : Sinauer Associates, Inc. Griffiths, A. J. F., Wessler S.R., Lewontin, R. C., & Carroll, S. B. 2008. Introduction to Genetic Analysis (9th ed.). . New York: W.H. Freeman and Company. Lewis, R. 2009. Human Genetics-Concepts and Application. Ninth Edition. New York: McGraw-Hill College Publishers. Read More