Oligonucleotide tagged nucleoside triphosphates, OTNTPs, which are substrates for polymerases and or terminal nucleotidyl transferases are provided as well as methods of making these OTNTPs. Further provided are OTNTPs with fluorescent dyes including energy transfer dyes, attached to the oligonucleotide chain, OTNTPs with unnatural bases incorporated in the oligonucleotide sequence and methods for incorporating these OTNTPs in DNA or RNA. Also provided are methods for using the oligonucleotides on OTNTPs for amplifying the oligo sequence on the OTNTP using an amplification method described above. Further provided are reactive bifunctional amidites, methods of making these compounds and methods for detecting single nucleotide polymorphisms using the above OTNTPs. Methods for detecting differential gene expression using the OTNTPs and methods of separating specifically modified DNA or RNA using the OTNTPs are also provided.