2'-3' dideoxynucleoside triphosphates (2'-3'ddNTP) are similar to deoxynucleoside triphosphate(dNTP) except 3'-OH group which is absent in 2'-3' ddNTP. The 3'-OH group is the site where new dNTPs are added by DNA polymerase enzyme.
The absence of 3'-OH group in ddNTP results in the formation of truncated DNA fragments.These fragments are analysed in the DNA sequencing process.
