Difference between revisions of "Unvalidated or Improper Forensic Science"

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Despite the fact that DNA is unique to each individual, as a defense lawyer you must always be cautious. Always have in mind that DNA profiling is a very complex affair, with many different technical stages. At any one of these stages problems may occur that could invalidate DNA profiling evidence. These may include problems with the quality, quantity and purity of the DNA possessed.
 
Despite the fact that DNA is unique to each individual, as a defense lawyer you must always be cautious. Always have in mind that DNA profiling is a very complex affair, with many different technical stages. At any one of these stages problems may occur that could invalidate DNA profiling evidence. These may include problems with the quality, quantity and purity of the DNA possessed.
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* '''Quality''': A problem with DNA evidence may result because of its quality. If the DNA sample has been left in adverse conditions for even a period of 24 hours, the sample may become degraded, and the evidence would no longer be able to be tested (i.e moist, warm conditions). The bands will not be clear, but will be smeared. Incidentally, when DNA is submitted as evidence, one must ensure that the test showing that it is not degraded must also be admitted.
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* '''Quantity''': The quantity of the DNA sample may cause problems, It is very difficult to create a DNA profile if the sample is not very big. In addition, if the sample is too small it may be used up entirely by the prosecution, leaving the defence with no ability to carry out their own tests.
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* '''Purity''': Another possible problem that may occur is the contamination of the DNA sample. A sample obtained for example by a bloodstain at the scene of the crime, may not be a pure sample, but might actually be a mixture of the victim's blood and that of the assailant's. The impurity of the sample may also come about from bacterial DNA at the crime scene, or even from the laboratory.
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== Data of erroneous DNA testing ==

Revision as of 09:12, 1 June 2010