The main principle of the PCR-electrophoresis method (Gap-PCR method) is to conduct electrophoresis of PCR products; and the charge effect and molecular sieve effect of DNA molecules while swimming. Under a certain electric field strength, the migration speed of DNA molecules depends on the molecular sieve effect, that is, the size and configuration of the molecules themselves. Therefore, different DNA molecules are isolated and compared with Marker to determine the result. The PCR-reverse point hybridization method uses a biotin-labeled probe to hybridize with a specific amplified PCR product, and a hybridization signal can be displayed through a corresponding color reaction to judge the result.