DNA+Analysis

=DNA Analysis =

====DNA analysis begins with the use of genetic markers including short tandem repeats (STR), single-nucleotide polymorphisms (SNP), mitochondrial DNA (mtDNA) and Y-chromosome DNA. Polymerase chain reaction (PCR) is a method used to amplify the DNA samples. Locating STR markers is the most utilized method of DNA analysis. There are 5-20 alleles on the STR loci that are relevant to victim identification because of the high levels of polymorphic informativity content (PIC) (Zietkiewicz et al., 2012). Polymorphic informativity content is important because it can give unique information about the individual. The United States government uses a standard, called the Combined DNA Index System, or CODIS, that states that a specific set of 13 STR loci have to be present in any DNA typing experiment to be carried out. ====

====Polymerase chain reaction (PCR) primers amplify segments of DNA. Primers have a fluorescent dye, and the two chromosomes it’s amplifying have different alleles and a different number of repeats at the same locus. The products obtained from the PCR have different sizes and are exposed to electrophoresis on a thin PAGE in a capillary tube. Fluorescent bands are obtained and scanned by a laser to generate peaks that correspond to the size of each PCR product and the length of the STR in that allele. ====

====PRC primers designed to target the amelogenin gene on the X and Y-chromosomes can determine sex of the individual. SNPs are advantageous for identifying disaster victims, because they are single base substitutes at certain locations on the DNA molecule so the DNA fragments are very short. Mitochondrial DNA is DNA that is acquired from the maternal lineage of the victim. Mitochondrial DNA molecules are small and circular, which are also advantageous for identifying disaster victims because the circular shape allows them to be more resistant to harsh environments. ====

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