Before 1990, the majority of U.S. forensic laboratories were associated with law enforcement agencies, yet received a relatively small portion of their given agency’s total budget. In general, laboratories performed a range of services including drug testing, firearm examinations, bullet comparisons, paint chip characteristics, assessment of tool marks, serology, handwriting analysis, and fingerprint comparisons. Laboratory personnel received training in fingerprints, basic and advanced blood stain and bullet pattern analysis, evidence collection, and crime scene processing. Due to the length of time and high cost required to obtain probative information, large numbers of samples were not processed.
Law enforcement relied upon forensic laboratories to provide a basic level of discrimination of biological evidence. Analyses of this evidence in cases involving intimate contact were conducted using serological tests such as ABO blood typing and analysis of polymorphic isoenzymes such as Esterase D to enhance the power of discrimination. Discrimination of protein markers was achieved largely through immunological methods or electrophoretic methods using starch gels or isoelectric focusing plates. Phenotyping of biological evidence was possible but required technical expertise and was subject to certain limitations such as the need for fresh semen samples in the analysis of sexual assault evidence. Overall, the typing methods in use provided limited discrimination and lacked the capability to individualize biological evidence. In some cases, individuals who could not be excluded on the basis of serological analysis were exonerated years later through DNA testing.
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DNA testing is becoming more and more prominent in convicting criminals. All forensic chemists need is a tiny piece of DNA, multiply it with DNA polymerase, and match it with the criminals DNA, and BAM they are either set free or off to the stony lonesome for them. More and more cases are coming up where innocent people are getting let free and guilty people are getting put in jail. I've even heard of forensic scientists following suspects around to diners and getting the lip prints off of their glasses after they leave. Even that provides them with enough DNA to do their work. Forensics in general is becoming a pretty huge occupation, no longer are forensic scientists tied to just CSI. They are performing drug tests for big employers and steroid tests for athletes.
ReplyDeleteAlthough I am almost fully clueless when it comes to genetics, biology, chemistry, and all types of other science-based studies, this blog in particular really caught my interest. I'd watch CSI and SVU whenever I'd get a chance, and of course I'd stay up way past my bed time just to catch the ending, but not once did I ever take into consideration the idea that REAL people do these jobs everyday! I always felt that being a "super-sleuth" was just a hobby or a part-time thing. I never took the time to appreciate the hard work and efforts that forensic scientists do on a daily basis. I surely have a new found appreciation for those of you majoring in this field. Our society today would not be the same without you. Thanks for this blog. You've really opened my eyes to a whole new dimension.
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