In: Biology
How can PCR detect polymorphisms at STR loci? describe the process
Human DNA is 99.9% identical with only 0.1% variation in individual DNA. This variation is usually a result of Polymorphism forun in the short repeated sequences of DNA known as STRs. Genomic regions containing these repeats are very similar between closely related individuals, but different enough so that unrelated individuals are highly unlikely to have the same STRs.
In DNA fingerprinting, The STR loci are amplified by PCR using sequence-specific primers. These primers are designed in such a way that they can amplify the STR loci from any individual. These primers identify the STR loci in the indivuals are able to initiate replication of the entire STR region, thus providing a larger fragment of DNA for analysis. The resulting DNA fragments are then processed using electrophoresis. Separation and detection of these fragments results in a unique pattern of bands, often referred to as a genetic fingerprint, and it is this unique pattern that is ultimately used in criminal investigations and genetic analysis.