DNA Fingerprinting
...nother base: adenine (A) bonds with thymine (T) and guanine (G) bonds with cytosine (C). DNA is made up of subunits that are called nucleotides. Each nucleotide is made up of a sugar, a phosphate and a base." The number of adenine bases equals the number of thymine bases and the number of guanine bases equals the number of cytosine bases" (Brinton & Lieberman 1994). Genes tell the cell to make proteins, allowing the cell to perform certain functions. Genes can be mutated, which can be helpful or harmful. DNA testing was first developed in England in 1985. The chemical make up of everyone’s DNA is alike. "Scientists use their knowledge of the structure of DNA and its chemical properties to study and change DNA molecules" (Miller & Levine p.321). The difference between people or animals, is “the order of the base pairs. There are so many millions of base pairs in each person’s DNA that everyone has a different sequence” (Brinton & Lieberman 1994). Using these sequences every individual could be identified. However, it would be very time-consuming so “scientists use a shorter method because of repeating patterns in DNA.” (Brinton & Lieberman 1994). These don’t give an individual fingerprint but they can allow determining whether 2 DNA samples are from the same person or not. “Scientists use a small number of sequences of DNA that are known to vary among individuals a great deal and analyze those to get a certain probability of a match” (Brinton & Lieberman 1994). The uses of DNA fingerprinting are for paternity & maternity, criminal identification & forensics or possibly personal identification as well. Paternity analysis has been used to solve father identification cases and also more complicated cases such as confirming legal nationality and biological parenthood. DNA samples can be obtained from blood, sperm and even hair strands with small pieces of tissue at the base" (Miller & Levine p. 357). DNA can also be taken from skin cells or other genetic evidence left at the scene of a crime. DNA then "can be compared through VNTR patterns, with the DNA of a criminal suspect to determine guilt or innocence” (Brinton & Lieberman 1994). These patterns can also be used to identify a homicide victim, “from DNA found as evidence or from the body itself” (Brinton & Lieberman 1994). The use of DNA fingerprinting as a source to identify individuals is not likely to happen anytime soon. The technology required is expensive and not practical. There are also problems with DNA fingerprinting such as the probability, or technical difficulties. “The probability of a DNA fingerprint belonging to a specific person needs to be reasonably high especially in criminal cases. The difference in probabilities is particularly visible across racial lines. Further experimentation in the this area, known as populations genetics, has been surrounded with and hindered by controversy.” (Brinton & Lieberman 1994). The idea of an error is often not acceptable. If the wrong DNA is amplified, or created into “a much larger sample of genetically identical DNA from what little material is available"( Brinton & Lieberman 1994), the consequences can be damaging. "Different techniques are used to extract DNA from cell and to identify the sequence of bases in a DNA molecule."(Miller & Levine p.321) DNA first has to be extracted simply by opening the cell and separating it with a chemical procedure. Restriction enzymes, which are used to cut DNA precisely, cut the matching sequence. ...