Method For Synthesizing Single-Stranded Nucleic Acid

An inner primer pair comprising the following A) and B):

• when a first arbitrary sequence F1c and a second arbitrary sequence F2c are selected in that order from the 3′ terminus of the target sequence on the first DNA strand of the double-stranded DNA toward the 3′ terminus on the DNA strand and a third arbitrary sequence R1 and a fourth arbitrary sequence R2 are selected in that order from the 5′ terminus of the target sequence toward the 5′ terminus on the DNA strand,
• A) a primer containing sequence F2, which is complementary to F2c, and the same sequence as F1c in that order from the 3′ side toward the 5′ side, or a primer containing sequence F2, which is complementary to F2c, a recognition sequence of the following restriction enzyme, and the same sequences as sequence F1c in that order from the 3′ side toward the 5′ side, wherein the restriction enzyme is capable of
• a) forming a fragment having an overhanging 3′ terminus, and
• b) cleaving so as to make base sequences of the single-stranded regions of the fragments after the cleavage differ from each other;
• and
• B) a primer containing the same sequence as R2, a recognition sequence of the restriction enzyme, and sequence R1c, which is complementary to R1, in that order from the 3′ side toward the 5′ side.