The application of DNA test in human identification, as well as, relationship testing has become an integral part of criminal justice systems. DNA test can determine whether two or more persons are related and the nature of their relationship (Reno & Reinsten, 2005, p. 23). For instance, DNA testing has made it possible to identify a person and to obtain information about his or her gender, as well as, ethnic background. It is predicted that in the next few years, DNA testing will make it possible to identify a person’s age.
DNA testing involves comparing DNA markers from two different persons. If a match exists between the two samples of DNA markers, then it is likely that they came from the same individual (Reno & Reinsten, 2005, p. 32). If the samples are not identical but exhibit big similarities, then they are likely to have come from people who are related. Thus, DNA testing has significantly, changed the way criminals are identified in the criminal justice system. Today, DNA testing is considered the most reliable means of determining those who participated in a criminal offence. The popularity of DNA testing is attributed to the following advantages.
First, DNA testing requires very little clue to identify the criminals. This is because investigators can obtain DNA evidence from several different sources. DNA is contained in nearly all biological evidence. The biological evidences include saliva, hair and blood which are usually left at most crime scenes. However, insufficient amounts of DNA might be contained in some samples, thereby making it difficult to conduct a DNA test. The samples are normally analyzed in order to obtain a “DNA profile of the individual that the samples came from” (Stromatt, 2007, p. 25). If some suspects have already been arrested, their DNA samples can be collected and compared to the one obtained from the crime scene in order to implicate them. DNA profile databases have also been established to help investigators to identify suspected criminals by comparing the suspects’ DNA profiles with those that exist in the database. In this context, DNA testing increases the likelihood of identifying those involved in a crime.
Second, DNA testing is very accurate. Accuracy is enhanced by the use of correct procedures to collect and preserve the biological evidence obtained at the scene. Accuracy can also be enhanced if the forensic scientists use correct and acceptable methods to analyze the samples. The probability of one person’s DNA profile matching that of another individual is almost negligible (Stromatt, 2007, p. 27). Finally, technological advancements have made DNA testing more efficient. Today, the time required to conclude the test has decreased from eight weeks to two days.
DNA testing has the following disadvantages. First, DNA tests can not be used to “determine a motive for crime” (Stromatt, 2007, p. 28). Thus, it can not be used to prove that the people who were present at the crime scene had a motive to commit a crime or not. Second, the biological evidence such as saliva can be interfered with or contaminated if they are not well preserved. This can lead to identification of the wrong suspects. Despite these disadvantages, DNA testing has significantly improved the accuracy and efficiency of identifying suspects in the criminal justice system.