What Are Single Nucleotide Polymorphisms?

Single nucleotide polymorphism mainly refers to DNA sequence polymorphism caused by mutation of a single nucleotide at the genome level. It is the most common form of human heritable variation and accounts for more than 90% of all known polymorphisms. SNPs are widespread in the human genome, with an average of 1 in every 500 to 1,000 base pairs, and the total number is estimated to reach 3 million or more. SNP is a dimorphic marker, caused by the conversion or transversion of a single base, or by the insertion or deletion of a base. SNPs may be within the gene sequence or on non-coding sequences outside the gene. ^[1]

Single nucleotide polymorphism

The polymorphism shown by SNP involves only a single

The first is a large number of single-base mutations throughout the genome;

The second is distributed in the coding region of the gene, which is called cSNP, which is a functional mutation.

SNPs are unevenly distributed across individual genes or the entire genome:

(1) There are more non-transcribed sequences than transcribed sequences

(2) The frequency of non-synonymous mutations in the transcribed region is much lower than that of other mutations.

In genetic analysis, SNP has been widely used as a type of genetic markers, mainly due to these characteristics:

It is estimated that there is one SNP for every 1,000 nucleotides in the human genome, and there are more than 3 million SNPs in the human 3 billion bases. SNPs are found throughout the human genome and can be found in

Although there are four bases that make up DNA, SNPs generally have only two

Estimated with mixed samples

The dimorphism of SNPs also facilitates genotyping. Genotyping SNPs includes three aspects: (1) Chemical reactions used to identify genotypes. Commonly used techniques include: DNA molecule hybridization, primer extension, allele-specific oligonucleotide ligation reaction, flanking Probe cutting reactions and workarounds based on these methods; (2) The modes used to complete these chemical reactions, including liquid phase reactions, reactions performed on a solid support, and reactions that are both. (3) After the chemical reaction ends, the biotechnology system needs to be used to detect the reaction result.