摘要 |
The identity of a nucleotide of interest in a target nucleic acid molecule is determined by combining the target with two primers, where the first primer hybridizes to and extends from a location 3' of the nucleotide of interest in the target, so as to incorporate the complement of the nucleotide of interest in a first extension product. The second primer then hybridizes to and extends based on the first extension product, at a location 3' of the complement of the nucleotide of interest, so as to incorporate the nucleotide of interest in a second extension product. The first primer then hybridizes to and extends from a location 3' of the nucleotide of interest in the second extension product, so as to form, in combination with the second extension product, a nucleic acid fragment. The first and second primers are designed to incorporate a portion of the recognition sequence of a restriction endonuclease that recognizes a partially variable interrupted base sequence. i.e. a sequence of the form A-B-C where A and C are a number and sequence of bases essential for RE recognition, and B is a number of bases essential for RE recognition. The first primer incorporates the sequence A, the second primer incorporates the sequence C, and they are designed, in view of the target, to product a nucleic acid fragment where sequences A and C are separated by the bases B, where the nucleotide of interest is within region B. Action of the RE on the nucleic acid fragment provides a small nucleic acid fragment that is amendable to characterization, to thereby reveal the identity of the nucleotide of interest.
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