DNA is one of the popular methods used by criminologists today, DNA technique is also known as “genetic fingerprinting.” the name given the procedure by Cellmark Diagnostics, a Maryland company that certified the technique used in Great Britain; Lifecodes, the USA law enforcement agencies do commercial DNA identification used the DNA-Print test technique.
DNA or “deoxyribonucleic acid” is a unique genetic code of each individual. DNA represents a double-stranded chain of molecules that winds its system through the center of every nucleated cell in every living creature. From one person to another, the series in which molecules form the DNA chain differs. Within species, the number of similarities is greater than the number of alternations, but because of the uniqueness of DNA, no two intervals are exactly the same, except for identical twins (Bowers, 43).
For criminal purposes, DNA is extracted from a sample; it is then mixed with an enzyme that singles out the DNA chain at specific sites. The restriction elements that are created by this process differ in length, and a few of them contain the polymorphic DNA element. Next, the elements are sorted by length, using a method called gel electrophoresis: The elements are put on a gel and an electrical current is applied, causing the elements to move toward the positive electrode. Shorter elements move across the gel more quickly than do longer elements and, after a short time, the elements have lined up on the gel according to size. After the elements have paraded across the gel, the configuration is transferred to a nylon membrane called a blot (Fisher 65).
Comparing the elements from different samples to each other, criminologists can tell whether the samples match. In a paternity test, samples of blood are drawn from the individual and compared from the sample found at the crime scene. In a criminal investigation, the samples typically are blood from the victim, blood from the accused individual, and the samples from the crime scene, such as bloodstained parts of clothing the offender was wearing. If the DNA sample matches the sample of the offender’s blood, criminologists are willing to give evidence that the chances of the DNA on the sample coming from the offender are high (Kubic and Petraco 74).
These criminologists argue that the probabilities are frequently one in millions or billions that two persons would present an identical DNA code; the odds differ, depending on the people in question because there are racial and gender alternations in polymorphic strands, and a range of features are more common or less so. Therefore, these criminologists believe there is virtual evidence that the accused person commits a crime (Bowers, 76).
Another technique used by criminologists to determine DNA strands and similarity was developed by White and by Jeffreys. This technique is known as allele-specific testing. Criminologists use this test developed by the Cetus Corporation, to determine whether certain polymorphic DNA elements, known as alleles, are in a sample. This allows a detailed recognition of the DNA because large numbers of individuals may have any one unique allele present in their DNA. By questioning for a large number of alleles, it is likely to identify that a DNA came from one particular person out of 10,000 or 100,000.
The method is particularly useful when looking at small DNA fragments. Since DNA deteriorates so fast, it is not possible to get a large fragment to do testing using the Cellmark or Lifecodes methods. In the Cetus test, DNA is purified, then “amplified” with the help of a procedure called polymerase chain reaction (PCR). By heating and cooling the DNA samples with an enzyme, criminologists extract a few elements of a particular allele and compare it to as many as 10 million samples, it is enough to allow allele-specific probes to do their work. The enlarged DNA is “spotted” onto a membrane, and allele-specific probes are extracted (Kubic and Petraco 39).
As with other methods for identification, including Social Security codes, civil some critics are concerned about the abuse of DNA codes by administration officials to threaten and spy on individuals’ private lives, and these critics are marshaling their point of view against such use. For instance, Attorneys for the Project on Privacy and Technology of the American Civil Liberties Union (ACLU) criticizes the whole NCIC program of DNA databases: he states that DNA cedes matches a specific fragment to a specific individual, the digital database will allow law enforcement to round up offenders based on a cursory examination of DNA-sample tests from crime scenes (Kubic and Petraco 23).
As a result, courts are extremely aware of the unreliability of eyewitness evidence, even from a victim. In cases where DNA-codes evidence shows that a crime-scene fragment does not match the DNA from a person convicted of the crime, they are throwing jail doors open. Some police officers redo these suitcases; others do not. Still, more police officers settle in a plea arrangement (Bowers 55).
Taking into account human rights and constitutional rights, DNA codes can be obtained from three groups of individuals: spouses, parents, and children. These groups are allowed to be tested during investigations. The expertise is clearly here, it is getting more complicated, and those who use the know-how for criminal purposes are, more and more, being held to the highest principles of laboratory discipline.
They need to be, because individuals’ lives and destiny rest on their work. While DNA codes are used as a technique of inclusion—trying to prove guiltiness—came under serious attack throughout the 1990s, the method became more and more used as an instrument of exclusion—proving that a person could not have been responsible because blood or semen fragments decisively do not match. From the very beginning, the Innocence Project concentrated on cases where individuals convicted of murder or rape felt they had not been objectively represented. Usually, the main evidence was witness identification, which experts have shown time and time again to be untrustworthy. In this case, a DNA sample helped individuals to prove their innocence and exclude them from the accused (Rainis, 98).
Today, the FBI asks for federal legislation which allows the use of DNA samples in criminal investigations. In case the state’s authorities approve this norm, the FBI will collect the DAN data in the National Crime Information Center (NCIC), an FBI-directed network of data about crimes throughout the nation. The DNA database has existed since 1992 when the military services developed the first DNA-code database to be used in recognition of soldiers killed in military operations.
In June 1988, using know-how to recover DNA codes from bones, the officials were able to recognize the Vietnam-era “unknown” soldier as Air Force Lieutenant Michael J. Blassie, whose airplane was shot down near the village of An Loc on May 11, 1972 (Rainis, 87). These results show that DNA codes can be used as effective and reliable tools in the identification and recognition of an individual.
The state officials have offered proof that the fragments f DNA will be sealed and stored frozen, in order to ensure sample integrity over a long period of time. In regard to doubts about privacy and secrecy, the officials indicate that the data will be kept only as long as a person is in active military service or the reserves and will be deleted upon separation from the military; additional, the samples will be used only for recognition after death, not for criminal identification or paternity, except the case of law enforcement agency orders the military to turn over the DNA sample (Fisher, 54).
In spite of great opportunities proposed by DNA tests, privacy concerns and objectivity of results are still important for the society. It is evident that once DNA samples are collected they will not be destroyed after the death and separation from the military (Siegal et al 101). The records will be created in all states at a greater cost to the public. The proposed structure of DNA databases will lead to abuse of rights and freedoms of offenders as their DNA specimen will be tested more often than DNA samples of other individual (Siegal et al 98). The record is the possible solution, like the fingerprint record; thus it will violate rights of the populace.
The problem is that a criminal will know that he might be able to wipe out his fingerprint but leaving his DNA is another issue of analysis. Admit that the DNA test costs the state about, so it will demand millions of dollars to create and expend DNA database (Fisher, 13).
In sum, DNA test is one of the possible solutions to improve criminal investigations and prove a guild, but it still has a lot of limitations and weaknesses. DNA code is more useful for social services than just for police, that there are a lot of times when DNA identification is impossible. Criminologists are searching for methods to extract enough DNA fragments from bone to do a conclusive DNA coding. The police already is looking to DNA codes and record-keeping for its duty of positive identification of those killed.
Works Cited
Bowers, M.C. Manual of Forensic Odontology. Forensic Pr, 1995.
Fisher, B. A. J. Techniques of Crime Scene Investigation, 6th edn, CRC Press, 2000.
Kubic, TH., Petraco, N. Forensic Science Laboratory Manual and Workbook, Revised Edition. CRC; 2 edition, 2003.
Rainis, K. G. Blood and DNA Evidence: Crime-Solving Science Experiments (Forensic Science Projects). Enslow Publishers, 2003.
Siegal et al. (eds), Encyclopaedia of Forensic Sciences, Academic Press, London, 2000.