Fingerprint Techniques
Fingerprint identification has been around for a long time. Dating back to 1856, Sir William Hershel began using fingerprints by requiring people to not only sign business contracts but to impress their hand on the back of the contract. In the beginning, his intentions were not directed at personal identification. The print was simply used "to frighten him out of all thought of repudiating him signature" (The History of Fingerprints). As Hershel's fingerprint collection grew, he began to note that the linked impressions could prove or disprove identity. During the 1870's, Dr. Henry Faulds, a British Surgeon of Tsukiji Hospital in Japan, studied "skin furrows" after taking notice of finger marks on prehistoric pottery. He then devised a method of classification. Mr. Faulds passed on an explanation of his classification system, along with samples of the forms he had design for recording inked impressions, to Charles Darwin. However, because of Mr. Darwin's old age and ill health, he informed Faulds that he would pass the material on to his cousin Francis Galton. Sir Francis Galton, a British anthropologist, published a book called "Fingerprints." The book included the first classification system for fingerprints can be i
When DNA is subjected to restriction-enzyme activity, fragments of various sizes are formed. Each human family line has its own unique pattern of restriction-enzyme DNA fragments. This variation in patterns of DNA fragments found in human genetic lineages is called "restriction-fragment length polymorphism" (RFLP). Because each person, except for identical twins, is formed from different combinations of the genetic material from two family lines, the pattern of sizes of the fragments from an individual is unique and can serve as a "DNA fingerprint" of that person. This fact has been crucial in identifying assailants in a number of violent crimes where the victims were unable to do so. In these cases, bloodstains or semen stains on clothing, sperm cells found in a vaginal swab taken after a rape, or root hairs of the assailant were available for analysis. Extraction of DNA from dried blood or from one of the other sources, followed by enzymatic digestion, results in an unambiguous match of DNA fragments with DNA obtained from cells of the accused. Where bloodstains are available, clear-cut DNA fingerprints are obtainable from samples that are as much as four years old. Fingerprint patterns are divided into three general groups and eight subgroups. The most common is the loop, making up 65% of the impressions. The loop has one or more ridges that enter on either side of the impression. They re-curve, touch or pass through an imaginary line drawn from the delta to the core and terminate on or toward the same side of the impression from where they entered or originated. A loop has one or more ridges and must have one delta. There are two types of loops. The first being radial loops. The radial loop ridges flow in the same direction of the thumb, the radius bone. Ulnar loops ridges flow in the direction of the little finger, the ulna bone. The next type of pattern is the Arch. The arch had no type lines or deltas and makes up for 5% of the impressions. There are also two types of arches. One is the plain arch, which the ridges enter form one side of the impression and flow out the other side with a rise or wave in the center. A tented arch has the same description however, there is a ridge at the center that does not flow out the other side. Those ridges form a definite upthrust or angle of 90% or less from the horizontal plane. The last type of pattern is the whorl. Whorls make up 30% of the impressions and must have two deltas. There are four types of whorls. The first is the plain whorl, which is the most common. It has two deltas and at least one ridge making a complete circuit that can be spiral, oval, circular, or any variant of a circle. The imaginary line drawn between the two deltas must touch or cross at least one of the re-curving lives. The next is the central pocket loop whorl. This has two deltas and at least one ridge making a complete circuit. However, the imaginary line between the two deltas must not touch or cross any of the re-curving lines. Another type of whorl is the double loop whorl. This consists of two separate loop formations with two separate and distinct sets of shoulders and two deltas. The last type of whorl is the accidental whorl. This is a pattern consisting of a combination of patterns of two different types of patterns, except for the plain arch, with two or more deltas. The combination may include a loop and tented arch or double loop and central pocket loop. Also, underneath every pattern there are ridges running from one side to the other. The Federal Bureau of Investigation's (FBI's) Integrated Automated Fingerprint Identification System (IAFIS) is being developed to sustain the FBI's mission to provide identification services to the nation's law enforcement community and to organizations where criminal background histories are a critical factor in consideration for employment. The IAFIS will serve the FBI well into the twenty-first century and rep
Some common words found in the essay are:
Fingerprints Fingerprints, IAI Identification, Service Providers, System IAFIS, Division FBI, Hospital Japan, Extraction DNA, Juan Vucetich, William Hershel, Galton British, law enforcement, personal identification, ridge characteristics, primary fingerprint, fingerprint identification, primary fingerprint classification, imaginary line, loop ridges, classification system, delta core, type lines, deltas ridge complete, means fingers whorls, ridge complete circuit, central pocket loop,
Approximate Word count = 3311
Approximate Pages = 13 (250 words per page double spaced)
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