Forensic Science lecture 4 – 17/01/2013
Quiz: quiz after every 2 weeks, done through bb, posted midnight Sunday 12, close midnight Monday at 12. Video watched through class, Guest speaker: Heather Shacker – forensic biologist * biology section: identify of body fluids: blood, semen saliva, and DNA analysis * casework approach: find material, identify, analyse (DNA), evaluate/compare (after able to create DNA profile),then lastly interpret * how does that work? 3 main groups of DNA profiling
1) science team – evaluates it, receives info on the case and a the stuff submitted, read case history and what examinations will be conducted and done a case assessment 2) screening unit - special training, to examine the body fluids take small sample to DNA unit 3)DNA unit – process it, then all the info goes back to scientific team to further analyze. * Hypothesis – based testing: way to decide what exanimations will be conducted, what Qs will be answered? Available evidence, results obtained * Detection of body fluids: conduct visual examinations (overhead lights/mag lights) and alternative light source for which are not entirely visible (such as semen which can luminance) * Examination for blood:
1) chemical test (kastle-meyer) rub it on paper and apply some chemicals and to look for pink color change, then usually send it to DNA analyzis, to question human or animal. 2)Human origin – ABA Card – hema trace, to look for 2 lines for human, 1 for animal * Examination for semen.
1) chemical test- acid phosphatase and P30 found in very high levels of semen 2) microscopic exam – take small portion of the item if acid phosphatase found in the area and use under microscope and stain the slide * Examination for saliva: never able to 100% confirm so we check for a part – amalyaze 1) chemical test- amylase, phadebas test. Look for a blue color shade, color change fast is salvia or slow change can be other fluids * Limitations:
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