Methodology used for creating DNA profile from LCN This review describes DNA profiling issues inherent in a low quantity of DNA evidence and improvised strategies and modifications adopted by various forensic laboratories for successfully creating a DNA STR profile from low template DNA, and also describes risks and hesitant acceptability of DNA STR profiling results in courts associated with these strategies. Forensic laboratories face difficulties in solving cases because potential evidence becomes incapable of providing necessary information regarding the case ( Balding & Buckleton, 2009 Van Oorschot & Jones, 1997). Many forensic shreds of evidence, such as touch DNA, yield so lesser amount of staring DNA that it becomes impossible to create a complete DNA profile using standard conditions of PCR. Low copy number (LCN) is the profiling technique which has been widely used all over the world for creating interpretable DNA profile. The quantity of starting material of DNA is an important factor for successfully creating a DNA profile ( Gill, Whitaker, Flaxman, Brown, & Buckleton, 2000 Petricevic et al., 2010).
#Methods for statistical calculations of mixed dna samples full#
However, if the amount of DNA is less than 100 pg then it gets really difficult to get full DNA profile utilizing normal PCR conditions. It has been estimated that an easily interpretable DNA profile can be created from 0.2-2 ng of starting DNA amount with normal cycling conditions of 28-30 cycles of PCR. Multiplex PCR technique has an outreaching effect for creating a DNA profile by amplifying multiple genetic loci in a relatively short time ( Hill et al., 2007). DNA evidence in forensics is used for comparison purposes while solving criminal and non-criminal cases like rape, sodomy, murder, dead body identification, burglary, paternity and proof-of-death ( Luftig & Richey, 2001). It makes use of the PCR reaction to simultaneously amplify several STR loci present in the genome.
Sometimes DNA based evidence in criminal and non-criminal cases is so small in quantity that it cannot be analyzed using standard laboratory procedures, so advanced techniques and methodologies are required for their analysis and ultimate acceptability in courts.ĭNA STR (Short Tandem Repeat) profiling is an important technique for generating DNA profile that has revolutionized the forensic world. One of the most important evidence which has been widely accepted in the courts and found to individualize a person is DNA evidence ( Lynch, 2003). Evidence material collected from the crime scene is analyzed using the latest techniques in forensics to narrow down the investigation and to individualize a person. Since its arrival, forensic science has been helping mankind in solving various criminal and non-criminal cases.
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