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Accurately describe the basic techniques of DNA extraction, PCR and DNA electrophoresis...

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lizg10 | Student, Undergraduate | eNotes Newbie

Posted February 2, 2010 at 5:02 AM via web

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Accurately describe the basic techniques of DNA extraction, PCR and DNA electrophoresis use by Forensic Scientists?

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versatilekamini | College Teacher | Valedictorian

Posted February 5, 2010 at 1:08 AM (Answer #1)

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In recent years, a new technique called gel electrophoresis has been used, for separation of large sized DNA molecules, sometimes representing whole chromosomes. Using this technique, the segment of different sizes can be separated. Gel electrophoresis involves movement of fragments under a high voltage electric current.

Polymerase chain reaction (PCR) is used to make millions of exact copies of DNA from a biological sample. DNA amplification with PCR allows DNA analysis on biological samples as small as a few skin cells. With RFLP, DNA samples would have to be about the size of a quarter. The ability of PCR to amplify such tiny quantities of DNA enables even highly degraded samples to be analyzed. Great care, however, must be taken to prevent contamination with other biological materials during the identifying, collecting, and preserving of a sample.

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