How do you use PCR-STR to identify gene polymorphism?

PCR-STR (Polymerase Chain Reaction - Short Tandem Repeat) is used to identify gene polymorphism by amplifying specific regions of DNA that contain short tandem repeats, which are variations in the number of repeat sequences. By designing primers that flank these regions, PCR can selectively amplify the target STRs from a DNA sample. The resulting PCR products are then analyzed through methods such as gel electrophoresis or capillary electrophoresis to determine the lengths of the amplified fragments, which correspond to different alleles. Variations in the lengths of these STRs among individuals can indicate polymorphisms, aiding in genetic diversity studies, forensic analysis, or population genetics.