Forensic Science: DNA Technology Deoxyribonucle

DNA technologies have completely modified the practice of forensic biology. Before their introduction, scientists once attempted to either associate or exclude forensic specimens and criminal suspects using the ABO blood group system. Unfortunately though, these genetic markers have various inherent faults. For instance, sample size can be a problem; it was often insufficient. In addition, blood group evidence can easily become contaminated. Many times, such difficulties rendered the ABO system analyses virtually useless (Sajantila & Budowle 637-642).

In contrast, DNA profiling has dramatically increased the quality of evidence available to law enforcement agencies. DNA methods provide a far greater discriminative capability than conventional blood grouping or, for that matter, even fingerprint examination (Davies 95). An individual's genome is unique (Young et al. 882). With DNA methods, minute amounts of virtually any biologic specimen can therefore be used for identification purposes. DNA profiling is essentially a vastly improved analog

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ypically estimate that the odds of two different DNA sources providing in an exact match are as low as 1 in a million (Brownlee & Guttman 31). Of course, positive identifications must always be assessed with a thorough understanding of how forensic science applies DNA techniques. Typically, the DNA tests themselves take about six weeks to complete and may cost several thousand dollars per sample (Davies 97). Genetic material is obtained from innumerable body tissues and fluids: blood, saliva, bone, skin, and hair samples can all be used for the analyses. In addition, DNA testing can also be performed on old and decomposed specimens. Furthermore, the tests only require very small sample quantities. Successful results have been obtained, for example, from semen stains half the size of a dime and the root cells from as few as ten hairs. Moreover, when polymerase chain reaction methods are employed, only minuscule specimen quantities are required (Young et al. 882). The polymerase chain reaction amplifies genes; it can actually be used to replicate denatured DNA fragments the size of a few hundred base-pairs. Once amplified, this DNA can then be analyzed using conventional molecular analytic methods (Young et al. 882).
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Approximate Word count = 1638
Approximate Pages = 7 (250 words per page)