Databases
Many states in the US, led by the example of California, are now building databases of the DNA profiles of individuals who have been previously convicted of a violent offense. As these databases grow in size, so will their power to identify previous violent offenders, as many murders and rapes are committed by individuals who are repeat offenders.
New profiling methods
As explained previously, every cell contains 23 pairs of chromosomes, and so each gene is present in two copies.
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Discussion |
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Should convicted felons retain the right to privacy over their DNA profiles?
{Dis: Discuss arguments for and against.}
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However there is an exception to this general rule. Cells contain thousands of small organelles known as mitochondria, each of which possesses their own DNA. So, a cell contains many more copies of mitochondrial genes than VNTR or STR genes. This can be important when the amount of biological samples are limited or are in bad condition.
Such is the case for many victims of the World Trade Center disaster. Many were extremely badly burned, with little biological tissue left intact. Many body fragments were only found months after, and in an advanced state of decomposition. In such instances there is often insufficient DNA for VNTR or STR analysis, but enough to analyze the mitochondrial DNA.
At present, to use mitochondrial DNA to identify individuals, we must read and analyze the sequence of the "letters" or bases in the DNA from one region of the mitochondrial DNA--a process that is too expensive and time-consuming for normal use. However, new technology currently under development promises to make mitochondrial DNA analysis much cheaper and quicker such that it will compete with STR and VNTR analysis. Still other technology under development will radically speed up the analysis of STR loci.
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