Genetic polymorphism refers to the fact that the structure or nucleotide arrangement of the same gene may not be identical in different individuals, and that it is a variation of an allele, which does not necessarily affect the function of the gene, but can be used as a marker to distinguish between individuals. Polymorphism refers to the simultaneous and frequent existence of two or more discontinuous variants or genotypes or alleles in a group of organisms, also known as genetic polymorphism or genetic polymorphism. Genetic polymorphisms usually exist at a certain frequency, and the most common genetic polymorphisms are single nucleotide polymorphisms (SNPs), which can be a substitution, deletion, or insertion of a single nucleotide. And restriction fragment length polymorphism analysis (RFLP) refers to the digestion of DNA with the same restriction endonuclease, in different individuals of the same species of organisms, there will be different lengths of restriction fragment types, these different DNA fragments in different strains of bacteria show polymorphism, according to which polymorphisms can be distinguished between the strains of genetic variation. Gene polymorphism is a specialized knowledge in biogenetics that needs to be combined with other related knowledge to better understand the human system.