Free Forensic Science Essay Sample
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Forensic science is a professional field that examines and describes data, information or any other evidential material that that is found in the crime scene and can be used in the courts of law. This field employs the laws of science in order to come up with evidence to a case. When carrying out investigations, investigators and crime officials carry all the objects from the place of criminal events or even from the individual or substances that were involved in a crime. Forensic science specialists then examine these pieces of evidence and give their results, according to what they discovered from the samples (White 2010, p. 2). These scientists, therefore, always have to work hand in hand with the law enforcement in order to determine how a crime occurred. There are many fields that are under forensic science, and these include DNA testing, documentation analysis and linguistics among many other related fields. Forensic science is a field that keeps developing, and hence, there is always discovery of many elements that can help in reconstructing the activities of a crime scene. This essay is a discourse into the recent discoveries in the field of DNA with particular reference in the analysis of degraded DNA; the information in the paper will base its reference to various articles that reveal information about advances in DNA.
DNA and Forensic Science
Deoxyribonucleic acid, which is shortened as DNA, is a natural genetic component that is always situated in all cells of all living things. The component has three parts that enable cells to exist. DNA has many compositions, and among them is a thread, containing nucleotides. The composition of DNA in one individual is different from the composition of the same in all other individuals. This means that no human being can have the same DNA composition as the other, unless in rare circumstances such as twins. This discovery led to the initial forensic study of DNA in 1984. Scientists during these times needed a lot of samples of non-degraded DNA so as to find information. These samples are usually hard to find outside the human body (Butler 2009, p. 6). This discovery was not enough for the study of forensics; hence, there was need for more discoveries to enable law enforcers to find information in crime scenes that had very little samples that had DNA. In 1986, a new discovery was advanced that emphasised on the Polymerase Chain Reaction. This method allowed DNA material in a small sample of data and was magnified in order to examine the material in the DNA. This method was a key development in forensic science (Luftig & Ruchey 2000, p. 1).
Crime Scene Genetics
Discoveries in the technology of DNA have in the past helped in the reconstruction of how a crime took place in different crimes scenes. Current discoveries in forensics have led to many more discoveries in the technology of DNA. This has been done by examining exceedingly spoilt DNA and by also using RNA in forensic science. The use of DNA in identifying crimes started in 1986, when a man, named Colin Pitchfork, was convicted of murder (Phillips 2008, p.1). This case involved a teenager who had been raped and murdered, and the police did not have any clues on who had committed the crimes. This case took place in Leicestershire, England, and the police had to go from house to house in search of the man who had committed the crimes. They took samples of blood from each man until they found the criminal. Since then, every crime scene was well investigated for any objects that could be tested for DNA (Yeatts 2001, p. 9). In 1984, Alec Jeffreys discovered a new way of analyzing DNA in order to reduce mistakes that came with the identification of DNA. He discovered that the human DNA has patterns, in which each pair of patterns is repeated many times. This repetition is common among all individuals; however, the frequency, with which these patterns are repeated, is not the same in all individuals (Phillips 2008, p.1).
Each person has a unique frequency of the repetition of the DNA. This discovery was quickly integrated into forensic science, since law enforcers had to determine the individual a certain pattern of repetition of the DNA belonged to. This discovery was helpful in a way that it was not sensible to find two or more individuals with the same DNA pattern, unless these individuals were twins. This new development came to be widely used all over the globe and it was so effective; and yet, there were still more discoveries to be made. The polymerase chain reaction came into being and was put forward by Kary Mullis. It allowed discovery of information from crime scenes that had an intensely low amount of DNA. This method is still being used up to date (Phillips 2008, p.1).
STR profiles and databases
Crime laboratories all over the globe use short tandem repeats that contain DNA, but the replicating patterns of DNA are always shorter. STRs are also different among all individuals. This discovery has made law enforcers in the United States to create large databases of STRs that contain data about individuals who have been convicted or even those that are suspected but have not yet been caught. United States laws allow policemen to make a DNA database that includes DNA profiles from convicted criminals, suspects and even missing individuals (Phillips 2008, p.2). This database is called the Combined DNA Index System. In this way, when the police find information from a crime scene, they can compare this information with the DNA samples from their databases, so as to easily catch a criminal or acquit innocent suspects. The DNA database also consists of STR that is found on the X and Y chromosomes and is useful in also identifying the sex of the individual the DNA belongs to. Nations that have DNA databases have caused many debates in relation as to whose DNA is contained in these databases and how is the information used. This has led many nations to only have DNA databases of criminals that have been convicted and all the suspected criminals (Phillips 2008, p.2).
Analysis of degraded DNA, using STRs and SNPs
Scientists and nations are often in search of new methods, in which they can identify criminals, using DNA. One way, in which this can be done, is through compiling DNA information in national databases. However, individuals have had a difficulty in identifying what types of genetic indicators should be used as new data that constitutes national databases. The choice lies between STRs and mini-STRs and SNPs. These elements have been tested by European nations and the importance of these new elements is that they will be useful in identifying intensely degraded DNA (Dixon et al. 2006, p.33). A study that involved European laboratories and United States laboratories was carried out in order to test which method can be used to create information from degraded DNA. Each laboratory was given STRs, mini-STRs and a sample of degraded DNA stains, which was mainly blood and saliva. The laboratories tested the samples they were given, and the results that were sampled confirmed that mini-STRs were the best genetic material, in which to test samples from the criminal scene. Thus, the mini-STRs were found to be most effective in trying to find evidence of crimes from a crime scene (Dixon et al. 2006, p.34).
Analysing degraded DNA samples can be difficult since these samples do not contain enough genetic material that can actually lead to the individuals who are involved in a criminal offence. Studies show that smaller sized PCR products are really useful in analysing degraded DNA samples such as the ones, found in crime scenes that involve many individuals (Butler 2005, p. 146). However, there is also need of more technological discoveries that will magnify the degraded DNA samples in order to make them visible for scientists who specialize in forensics. One discovery that has made this possible is the mini-STR, which increases the size of DNA among samples, found in the crime scene (Schade & Klevan 2007, p.1). Mini-STR was first used by the Forensic Science Service. The service analysed the behaviour of mini-STR in small samples of DNA under exposure to a lot of heat. The research found out that using mini-STRs in analysis of samples increased the ability of discovery of DNA material. Mini-STRs can, therefore, be very instrumental in analysing data that contains intensely degraded DNA samples (Schade & Klevan 2007, p.1).
The role of the law in improving DNA technology
Police officers and forensic scientists often show their need for quick development in DNA technology. However, it is not only these two groups that show interest in this field, legislators also show their interest in the need for further advances in DNA analysis. In the United States, 44 states currently emphasise that there should be DNA from criminals (Butler 2011, p. 125). The rest of the states either need DNA from individuals that have been arrested or individuals that have gone missing. Some states recommend that DNA samples be taken from weapons and objects that have been involved in crimes. This shows that state leaders are also interested in the field of DNA technology; and it can only be hoped that these legislators will push for more advancements in DNA analysis (Schade & Klevan 2007, p.2). Mini-STR technologies help in identifying samples that have the least DNA in them. With increased technological advancement, the mini-STR may, perhaps, lead to the discovery of data from very minute samples from a crime scene. The expansion of this field of study will enable forensic scientists to provide more detailed and accurate information about crime scenes and objects from the crime scene. This, in turn, will facilitate the solving of more crimes in society and bring justice to those who require it (Schade & Klevan 2007, p.2).
Use of DNA in solving cases of missing persons
Individuals, ranging from children to even the old aged, often disappear from their homes from day to day. Some of these individuals get to return to their homes, while others disappear forever, never to be seen again. The technology of mini-STR can be functional in analysing the DNA samples of these individuals, and therefore, being able to trace them and identify what really did happen to them. Many skeletons have been taken from the ground; while other are stored in offices; and yet, nothing has been done to identify who these remains belong to. It has been noted that cases of missing persons often reappear from time to time. Examining samples of human remains can be difficult, because most of the times it is challenging to get DNA from the skeletal because they are too old or damaged. It is also difficult to get DNA from these samples because of environmental extremes such as humidity, temperature and acidity of the soil. However, scientists note that there is still hope, as mini-STR can be used to identify genetic material in the samples of skeletons and remains of missing persons. This will be useful in identifying what happened to these people and how did they meet their tragedies (Schade & Klevan 2007, p.2).
Forensic Mitochondrial DNA Analysis
Between the years 1999 to 2005, DNA samples were extracted from skeletal remains. Mitochondrial DNA was extracted from almost three quarters of the samples. These skeletal were grouped into two main categories; there were the samples that were brought in by law enforcers and there were samples that were brought in by families and friends who wanted these skeletal identified in order to answer some questions. The skeletons that were brought in by law enforcers had a lot of mt-DNA in them, while this was contrary to the skeletons that belonged to family and friends. The skeletal remains, brought in by law enforcers, had 25 years and below, while those brought in by families and friends were estimated to have 50 years and above (Nelson & Melton 2007, p.2). It was, therefore, noted that the older the skeletal, the lesser the DNA material it contained. The study concluded that the age and condition of a skeleton sample depended on the amount of DNA sample material contained. Samples that had less age contained a lot of DNA materials, while samples that were older had less DNA. Samples that had been stored in good conditions had more DNA material as compared to samples that had been poor stored. In the field of forensics, individuals need to store samples in good conditions so that they can be useful in future cases. In addition, it is advisable for these individuals to perform tests on samples, once they pick them, rather than to wait, because the older these samples get the lesser the amount DNA they contain (Nelson & Melton 2007, p.4).
Strategies to obtain DNA
There are different ways in which law enforcers can obtain DNA from individuals. These ways are stipulated by the law in most states. One way, in which this can be done, is through a court order. The court can always decide that an individual needs to provide DNA material so that it can be compared with material from a crime scene or to just ensure that the individual is not involved with a crime at all. DNA material can also be obtained through voluntary spirit. An individual who may be suspected may be asked to give their blood or any other sample, in which DNA can be extracted. The law can also be useful in finding DNA material. In most states, the law provides that criminals who have been convicted and individuals who have been arrested provide their DNA. This is an important way to obtain DNA for use in cases and court proceedings. Abandonment is also another way, in which DNA material can be obtained. In this method, a law enforcer observes an individual in a place, for instance use a cigarette, or take a drink. Once the suspect leaves, the law enforcer goes to collect DNA sample from the item, used by the individual (Dale, Greenspan & Orokos 2006, p. 7). These strategies are ordained by the laws of a country since it would be illegal to try and obtain personal information of an individual without their permission.
Non-human species in forensics
Forensic examination of animal material has also been employed, when an animal is involved in the crime scene. The sample materials that are from animals are usually animal fur and even animal excretion. Cases that involve animals include cases such as unlawful buying and selling of rare species. The most common samples that law enforcers use are fur that may be mixed up with other items in the crime scene. One of the best examples of cases where an animal was involved was a murder case, where a young girl was killed. The scene of the crime had dog fur, and the DNA of the dog fur matched the DNA of a dog belonging to the individual who was suspected to have killed the girl. Plant samples can also be evidence in the crime scene, just like animal samples do function. Microorganisms can also be used in finding evidence in a crime scene. Law enforcers can collect samples of this such as food, which can be analysed to prove that indeed an individual was involved in a crime (Jobling & Gill 2004, p. 748).
The study of DNA technology recognizes and eliminates suspects in reference to law and law enforcement. The fact that DNA is included and always considered in tackling crime is entirely encouraging since individuals feel safe because of the reason that there is a believable way, in which to identify criminals and bring them into justice. DNA has been used in different case like murder case, rape cases and even burglary. This is one advantage of using DNA to trace criminals and find out what really happened at a crime scene. DNA is also useful in finding missing persons and even in curbing illegal business in endangered species. The modern technological advances in DNA examination are enough proof that governments and individuals are determined to control crime. We look out for more advancement that will make the work of law enforcers and other stakeholders even much easier than it is today. However, DNA manipulation does not only have a good side of it, there are also disadvantages, engaged in the field. Such disadvantages include errors that forensic scientists may commit, when carrying out their research. It is the hope of everyone that there will be more technological advances in DNA screening so as to avoid these challenges.