SNP-BASED Genotyping

DNA profiling technologies >> Technological Solution >>

All chromosomes of any species are subjected to various types of sequence variations. SNPs (single nucleotide polymorphisms) are DNA variations that occur at the level of a single nucleotide, usually in a binary form (two possible alleles). In the human genome the estimated number of SNPs is 10 millions. A recently completed project in its first phase, the HapMap project, has established a sort of array of the human SNPs allowing the identification of the so-called haplotype blocks (regions of the genome in which SNPs are co-inherited, therefore defined by a lower number of tagging SNPs).

An high throughput approach at SNP genotyping is represented by DNA microarrays, an application still very expensive but very powerful. The information content of SNPs with respect to STRs is calculated in 3 SNPs accounting for 1 STR.