Patent ID: 8431366

Claim:
A method of DNA amplicon fragment analysis comprising: i) annealing an oligonucleotide primer to a denatured DNA template such that, the oligonucleotide primer anneals to a complementary oligonucleotide sequence on a strand of the denatured DNA template to form a primer-template complex, wherein the oligonucleotide primer comprises at least one modified purine nucleobase comprising the structure: wherein R 1 is selected from hydrogen, halogen, fluorine, chlorine, bromine, iodine, azido, nitro, cyano, unsubstituted or substituted amino, C 1 -C 6 alkyl, C 1 -C 6 alkynyl, C 1 -C 6 substituted alkynyl, unsubstituted or substituted phenylalkynyl, and unsubstituted or substituted aryl; at least one said modified purine nucleobase is no more than 3 nucleotides from the 3′ terminus of the oligonucleotide primer; and the oligonucleotide primer is extendable at its 3′-end; ii) extending the primer portion of the primer-template complex in the presence of extendable nucleotide triphosphates and non-extendable nucleotide triphosphates to form one or more DNA amplicon fragments; and iii) detecting the DNA amplicon fragments, wherein the oligonucleotide primer comprising at least one modified purine nucleobase no more than 3 nucleotides from the 3′ terminus of the oligonucleotide primer significantly reduces the formation of primer-dimer amplicons.