| abstract |
A probe polynucleotide binds to a target nucleotide sequence in the nucleic acid of a biological sample, and then is enzymatically extended in the 3'-direction with a mixture of nucleoside triphosphates including at least one nucleoside triphosphate that has been detectably labeled. After separating extended hybrid from unreacted nucleoside triphosphates, detectably-modified nucleotides which have been incorporated are determined. In some forms, the 3'-terminal nucleotide of the probe polynucleotide is selected to form a matched pair with some sample strands, but a mismatched pair with other sample strands. In such cases, if the primer dependent enzyme used for extension is one lacking 3'-exonuclease activity, then only those hybrids forming such a matched pair will be extended and subsequently determined. |