In our day to day activities, we are surrounded by science. In our lives, science plays an extreme role. DNA is the abbreviation for Deoxyribonucleic acid. It is present in all organisms, whether it is a bacteria, bird or mammal. DNA is a long molecule that carries a particular genetic data; it is located in every cell in a human body except the red blood cells. DNA profiling is easy acquire and very accurate in identifying a person. There are many different ways a forensic expert or a police officer can get DNA samples. In criminal cases, DNA samples help solve many crimes.
However, it also releases innocent people from prison. DNA is known to be he best thing that happened to forensic science since the advent of finger printing. Literature about DNA DNA is considered as the blueprint of our lives. The discovery of DNA began in the 1800s. The origin of DNA was discovered by Gregor Mendel the “Father of Genetics” in 1857 while he was performing an experiment of genetics with pea plants (Schwarzbuch, Smykal, Dostal, Jarkovska and Valova, 2014). Years few later, Johnann Friedrick Miescher began to follow Mendel studies and discovered the molecules of DNA.
Moreover, the use of DNA in Forensic science did not receive a breakthrough until the 1950s. James Watson and Francis Crick solved the genetic puzzle and discovered the structure of DNA (Portin, 2014). James and Crick were the first to discover the structure of DNA after following the work of pioneers before them. They came to a ground-breaking conclusion about the structure of DNA in 1953 (Portin, 2014). In 1980s, the discovery of DNA testing began. DNA in Forensic Before the 1980s, the court and criminal investigations were relying on eyewitness testimony as the key source of evidence,
However, in 1984, DNA became the “magic bullets” of criminal investigation, after the initial process of DNA testing was invented by British geneticist Alec Jeffery (McDonald, 1998). Studies shows, in every human most DNA information are the same, but the “junk code” between each person repeats are unique. Junk DNA used in a criminal investigation is found in saliva, sexual fluid, blood, perspiration, skin tissue, bone marrow, dental pulps and hair follicles (Butler, 2012). While Jeffery was analyzing the junk code he found in DNA, he noticed that 10 to 100 base pairs of certain sequences repeated multiple times.
In criminal investigation before Jeffery’s discovery, a blood drop found at a crime scene could only reveal the person’s blood type. Today, DNA forensic can reveal a person’s gender, race, susceptibility to disease and propensity for high aggression or drug abuse (Butler, 2012). DNA Fingerprint DNA fingerprint is also known as DNA typing or DNA profiling. There are thirteen standard tandem repeats operate in todays’ forensic to create a DNA profile (Butler, 2012). The techniques are used to compare and analyze DNA from separate sources.
DNA fingerprint has become one of the most powerful techniques that is used in a criminal investigation to identify suspects (Sierps and Kloosterman, 2003). Moreover, scientific DNA evidence is a key component in court cases. This process work base off the fact that no two people have the same DNA, except for twins or multiple (Dutelle and Becker, 2012). The technique of DNA profiling can identify the person accountable of a violent crime from physical evidence left at a crime scene. Police use DNA fingerprint to extend the crime scene investigation.
DNA profiling is used to compare evidences found at a crime scene to a suspect (Sierps and Kloosterman, 2003). DNA evidence helps establish a connection with a suspect to a crime scene. Forensic experts compare the evidence found at a scene with profiles stored in CODIS of previous offenders. Therefore, with an existing offender, DNA forensic expert will have many leads from the evidence found at a crime scene. However, without existing offenders, investigator will not receive a direct profile of the right suspect. DNA evidence has an advantage because of its’ longevity.
Although it will deteriorate if expose to sunlight, it can remain intact for centuries under proper condition (Sachs, 2004). The durable of DNA allows experts to reopen and reexamine the evidence in old cases. DNA profiling can also linked crimes together if the same DNA found at multiple crime scene, exonerate innocent suspect and narrow suspect pools. DNA profiling began the 1980s, and it is very successful in crime scene investigation. It was first developed in 1985, but it was not until 1986 it became a part of criminal investigation. In 1986, DNA was first used in a criminal investigation by Alec Jeffery (Brownlee, 1992).
DNA profiling became public after two young girls were sexually assaulted and brutally murder in London (Lee and Tirnady, 2003). In the case, fingerprint and semen were collected from the rape and murder scene to analyze. DNA evidence was first introduced in the United States in 1987 (Hammond, 2010). Tommie Lee Andrew, a Florida rapist became the first person in the United States to be convicted as a result of DNA evidence; then the following year, a Virginia man called the “Southside Strangle” was also link to rape cases and murder by DNA evidence (Hammond, 2010).
DNA evidence also helped capture Gary Ridgway, the infamous “Green river killer” of Washington State (Hammond, 2010). Testing of the Innocence’s DNA evidence does not always put people in prison, it also helps release them from prison. Studies show DNA database is not only speeding up crime solving, it is also exonerating the innocent at a rapid pace. There are hundreds of people in prison for crimes they did not commit. According to the National Registry of Exoneration, as of April 13, 2017, 446 people have been exonerated in the United States.
In which, 263 (41%) are African American, 142 (32%) Caucasian, 34 (8%) Hispanic and 4 (1%) others. There are 432 (98%) male and 11 (2%) female exonerees in based on DNA testing since 1986 (the National Registry of Exoneration, 2017). The first case of exoneration in the United Sates occurred in 1989 involving Gary Dotson (the Innocence Project). He was convicted of rape based on an eyewitness testimony. Studies show an exoneree base DNA evidence served an average time of approximately 13. 6 is years in prison.
However, the longest term served by a DNA exoneree is 35 years (the Innocence Project). Using DNA to solve crimes DNA is generally used to solved crime in two ways (Using DNA to solve crimes). DNA samples are taken from suspect to compare with the DNA evidence found at the crime scene, in cases where a suspect is identified. However, in case where there is no suspect identification, DNA samples from the crime scene is analyzed and compare through CODIS (Using DNA to solve crimes). CODIS can link evidence from one crime to another if the database found a match.
There are three steps forensic expert takes in an investigation when using DNA. DNA crime solving technique are, collecting evidence in which is done in a protective matter to prevent evidence contamination. Experts wear gloves and look for evidence such as blood, body fluid or fingerprint during the collecting process. Then, the evidence is sent to the lab to get analyze. In the analyzing process, the DNA collected is analyze and compare by DNA analyst. The analyst will determine the pattern, and compare it to a suspect or run the DNA through CODIS (Using DNA to solve crime).
The final step is the matching procedure. The analyst used the DNA found to include or exclude a suspect from the investigation. If they find a match, it will prove that the suspect had connections to the crime scene or subject. The analyst will then further their testing to find an exact match. Conclusion Since the discovery of DNA profiling in 1984, the procedure has evolved greatly. DNA profiling is an extremely important invention that helps forensic expert solved many crimes.
In today’s criminal justice system, expert can rely on an effective and safe way of DNA profiling which provides a high evidential value in criminal investigation. The use of DNA testing has become the method of choice of linking a suspect to a crime scene. DNA evidences are the key piece of evidence in solving many court cases. However, it also helped free a lot of innocent from prison. DNA is a powerful tool in court cases to prove whether an individual is guilty of committing a crime or innocent.
