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The agitated detective barks, “I need that DNA now. There’s a killer on the loose, and I have to know if we’ve got him in custody. I don’t give a damn how busy you are . . . ” We’ve all been there, on the edge of the couch, watching a cop show on TV and hoping that the magic of DNA testing will give a clear answer to the question “DidHeDoIt?” And indeed, DNA fingerprinting, more accurately ‘DNA profiling’, has transformed crimefighting.… Read the rest “DNA profiling I”

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Gel electrophoretic separation of DNA fragments containing Variable Numbers of Tandem Repeats. Each vertical lane contains one DNA sample. PCR-amplified fragments have been labeled, with different probes having different fluorescent labels. The red bands are internal calibration markers. The positions of the bands reflect their different mobilities, which in turn reflect their lengths (larger fragments move more slowly in electrophoresis). Capillary electrophoresis and automatic recording are used today instead of gel electrophoresis.

DNA profiling resulted from the convergence of scientific curiosity, technological advances, and the desire to provide a social benefit.… Read the rest “DNA profiling II”

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Our bones, teeth and hair carry in them an encrypted GPS log of where we’ve been. If you lived in Seattle through your childhood and moved to Chicago ten years ago, that is indelibly written there. There will also be a record of what you’ve eaten recently. Advances in the science and technology of reading that information are having an impact on forensics, anthropology and agriculture, among other pursuits. At the heart of that technology lies a fundamental property of matter, which is that many of the atoms that make up all of creation come in subtle variations, variations that we are able to detect with great precision.Read the rest “Your travels are Written in your body”