**Abstract**

It is amazing to know that around 99.9% of the individuals genome among persons is alike, and only 0.1% of it differs in chromosome. This variance is accountable for the diversity in phenotypes and receptiveness of them to environmental effects. DNA variants are happening in numerous formulas. Mutations might be definite as order variants which happen in less than 1% of the populace, whereas the extra prevalent variant is identified as polymorphisms. More than 1% of the greatest public hereditary variants are known as single nucleotide polymorphisms (SNPs). In human genome, SNPs considered as plentiful figure of genetic variation, and their importance in contribution to many disease, drug efficacy, and side effects in addition to may represent a prophylaxis. SNPs represent a specific location at which more than one nucleotide is established and only two alleles at a SNP locus. More than 100 million SNPs have been recognized in human, in average each 300 nucleotide on usual. The gene which has more than one allele is a normal result of SNP. SNPs are not restricted to coding sequence, but may be associated with noncoding region. Many techniques are used to analyze SNPs and involve two phases, one for allele recognition and another for detection.

**Keywords:** SNP, allele frequency, point mutation, VNP, chromosome, gender, gene, VNTR, CNV, STR
