Human DNA is very similar to one another, but only about 0.1% is different from the next person. That 0.1% can tell a person’s eye color, hair color, and other physical features. DNA analyst are able to take a drop of blood, the size of a dime, and duplicate the number DNA found in that drop. With the ability to duplicate DNA, analysts can have a back-up, in the event a human error were to occur. Analyst can tell you exactly where your ancestors came from and the percentage that is still inside your DNA. DNA is a very powerful tool that can identify a murder if the individual left any blood, saliva, skin tissue, hair or semen. The education needed to be able make use of the DNA consists of a great deal of science classes.
So you ask, "How does this work to catch or release criminals?" DNA is very simple and small. Everyone has different patterns. Using certain machinery to detect a person's DNA solves these patterns. This evidence will create a future in crime scene investigation.
DNA forensics can also narrow down suspect pools, exonerate innocent suspects, and link crimes together if the same DNA is found at both scenes. However, without existing suspects, a DNA profile cannot direct an investigation because current knowledge of genotype-phenotype relation is too vague for DNA phenotyping. For example, a profile from a first time offender that has no match in any database may give the information that the criminal is a left handed male of medium stature with red hair and freckles. It would be impossible to interview every man who fits that description. However, with available suspects, DNA forensics has many advantages over other forms of evidence. One is the longevity of DNA. Although it will deteriorate if exposed to sunlight, it can remain intact for centuries under proper conditions (Sachs, 2004). Because DNA is so durable, investigators can reopen old cases to reexamine evidence.
Each human being has something called DNA. DNA is described as genetics and an extremely long macromolecule that is the main component of chromosomes and is the material that transfers genetic characteristics in all life forms. DNA constructs of two nucleotide strands coiled around each other in a ladder like arrangement with the sidepieces composed of alternating phosphate and deoxyribose units and the rungs composed of the purine and pyrimidine bases adenine, guanine, cytosine, and thymine. Each chromosome consist of one continuous thread-like molecule of DNA coiled tightly around proteins and contains a portion of the 6,400,000,000 basepairs that make up your DNA.
DNA profiling involves testing mini-satellites one at a time which then goes on to produce an image which is much simpler than genetic fingerprinting. It provides a pattern which is unique to a particular person and is therefore suitable for forensic purposes. (Turnpenny, P et al 2005).
DNA was only gaining momentum in 1980, when Sir Alec Jeffreys discovered something that would change our world, DNA Profiling. DNA profiling is the use or extraction of human cells to be profiled. Whether they are fresh or dried-out, the cells can be tested. (Suzanne Elvidge, “Forensic Cases: Colin Pitchfork, First Exoneration Through DNA”) Sir Jeffreys first started the process of discovering genomics ability to advance our society by applying this to different types of DNA. By doing so, Jeffreys discovered that there are billions of variations in DNA sequences. In fact, the human body has 10 million different sites at which one person’s DNA sequence can vary from another’s. (University of Leicester, “The Science Behind Genetic Fingerprinting”) Jeffreys’ discovery then allowed for DNA profiling to be used in the United Kingdom, where Sir Jeffreys conducted his research. With the research and testing performed in Europe, DNA profiling was now applicable in the United States. Detectives such as Joe Horgas took advantage of this
DNA fingerprinting, also known as DNA profiling, is a technique used in forensic science that identifies individuals based on various characteristics of their DNA. Although the DNA sequences between humans are 99.9% identical, DNA fingerprinting is able to distinguish between individuals due to the presence of specific sequences within the non-coding region of the genome known as satellite DNA. This satellite DNA consists of long stretches of DNA made up of repeating base sequences known as short tandem repeats (STR). These STRs considerably vary in length between individuals, particularly between unrelated individuals, allowing exact individuals to be identified. One major use of DNA fingerprinting is in
Law Enforcement keep notes on arrests that have founded people innocent of crimes, and retention of an innocent person's DNA can be charge or otherwise, seen as a invasion of that person’s privacy and civil liberties. Dr. Alec Jeffrey, a former professor at the University of Leicester laboratory, consulted with his lawyers to develop the new type of technique called DNA profiling. His technique would prove that DNA fingerprinting (profiling) can individualize evidence compared to the blood typing. DNA profiling compares 13 standard STRs to form a profile. The analysis used by the scientists, uses PCR and STRs to profile an individual. It is highly unlike that two individuals’ identical numbers of repeats for all 13 STRs, will match, which DNA fails is hardly never due to a successful match of 385 million to 1. This makes DNA profiling the most accurate tool in Forensics.
DNA is a long curved structure, made up of pairs of four specific bases: adenine, guanine, cytosine, and thymine, is the repository of a code from which all of our cells are made. The code is made up of base pairs which look like the
From cases such as OJ Simpson to Chandra Levy, DNA profiling also called DNA fingerprinting or DNA typing has played a major role in the criminal justice system. The law enforcement community uses DNA profiling to rule out or identify suspects. Unlike hair microscopy, bite mark comparisons, shoe print comparisons, and firearm tool mark analysis, DNA typing has been developed through massive scientific research and has undergone meticulous scientific evaluation (Innocence Project). DNA is a foolproof method of identifying a perpetrator of a crime.
The process of DNA fingerprinting in humans involves the replication and arrangement of extracted DNA, to create a pattern/fingerprint that is viable for comparison. This process involves the application of DNA extraction, digestion by restriction enzymes, Polymerase Chain Reaction (PCR) and gel electrophoresis. This results in a DNA profile with bands of varying widths that can be used for the comparison of genetic information. DNA extraction occurs in three stages. Firstly, a