PCR-reverse dot hybridization is commonly used for genotyping and gene mutation detection. The main principle is to point the probes to be used to the nitrocellulose membrane or the nylon membrane, each probe is marked with a number,  and then the DNA sample to be tested (usually the product specifically amplified by PCR) , The biotin label is pre-labeled on the 5 'end of the PCR primer, so that the amplified product is correspondingly labeled with biotin) to hybridize with it, so that the sample to be tested will be combined with a probe having a homologous sequence, and unbound DNA is washed to remove In the sample, since the DNA sample to be tested has biotin-based markers, the probe points combined with the DNA to be tested carry biotin-based markers, and then the hybridization signal can be displayed by the corresponding color reaction.