<P> STR analysis is a tool in forensic analysis that evaluates specific STR regions found on nuclear DNA . The variable ( polymorphic ) nature of the STR regions that are analyzed for forensic testing intensifies the discrimination between one DNA profile and another . Forensic science takes advantage of the population 's variability in STR lengths , enabling scientists to distinguish one DNA sample from another . The system of DNA profiling used today is based on PCR and uses simple sequences or short tandem repeats ( STR ) . This method uses highly polymorphic regions that have short repeated sequences of DNA ( the most common is 4 bases repeated , but there are other lengths in use , including 3 and 5 bases ) . Because unrelated people almost certainly have different numbers of repeat units , STRs can be used to discriminate between unrelated individuals . These STR loci ( locations on a chromosome ) are targeted with sequence - specific primers and amplified using PCR . The DNA fragments that result are then separated and detected using electrophoresis . There are two common methods of separation and detection , capillary electrophoresis ( CE ) and gel electrophoresis . </P>
<P> STR analysis is a tool in forensic analysis that evaluates specific STR regions found on nuclear DNA . The variable ( polymorphic ) nature of the STR regions that are analyzed for forensic testing intensifies the discrimination between one DNA profile and another . Forensic science takes advantage of the population 's variability in STR lengths , enabling scientists to distinguish one DNA sample from another . The system of DNA profiling used today is based on PCR and uses simple sequences or short tandem repeats ( STR ) . This method uses highly polymorphic regions that have short repeated sequences of DNA ( the most common is 4 bases repeated , but there are other lengths in use , including 3 and 5 bases ) . Because unrelated people almost certainly have different numbers of repeat units , STRs can be used to discriminate between unrelated individuals . These STR loci ( locations on a chromosome ) are targeted with sequence - specific primers and amplified using PCR . The DNA fragments that result are then separated and detected using electrophoresis . There are two common methods of separation and detection , capillary electrophoresis ( CE ) and gel electrophoresis . </P>
what do the letters str stand for as used in forensic science
what do the letters str stand for as used in forensic science
short tandem repeats
short tandem repeats