Primer, primer set, and nucleic acid amplification method and mutation detection method using the same

A primer for amplifying a target nucleic acid sequence,

• wherein the primer is a labeled nucleic acid including at least one of structures represented by the following formulae (16), (16b), (17) and (17b) and exhibits an exciton effect:
• where in the formulae (16), (16b), (17) and (17b),
• B is an atomic group having a natural nucleobase (adenine, guanine, cytosine, thymine, or uracil) skeleton or an artificial nucleobase skeleton,
• E is:
• (i) an atomic group having a deoxyribose skeleton, a ribose skeleton, or a structure derived from either one of them, or
• (ii) an atomic group having a peptide structure or a peptoid structure,
• Z11 and Z12 are each a fluorescent atomic group that exhibits an exciton effect, and may be identical to or different from each other,
• L1, L2, and L3 are each a linker (a linking atom or an atomic group), the main chain length (the number of main chain atoms) is arbitrary, they each may or may not contain each of C, N, O, S, P, and Si in the main chain, they each may or may not contain each of a single bond, a double bond, a triple bond, an amide bond, an ester bond, a disulfide bond, an imino group, an ether bond, a thioether bond, and a thioester bond in the main chain, and L1, L2, and L3 may be identical to or different from one another,
• D is CR, N, P, P═O, B, or SiR, and R is a hydrogen atom, an alkyl group, or an arbitrary substituent,
• b is a single bond, a double bond, or a triple bond, or
• in the formulae (16) and (16b), L1 and L2 are each the linker, L3, D, and b may not be present, and L1 and L2 may be bonded directly to B,
• where in the formulae (16) and (17), E is the atomic group described in item (i), and at least one O atom in a phosphoric acid linkage may be substituted with an S atom,
• in the formulae (16b) and (17b), E is the atomic group described in item (ii), and
• in the formulae (17) and (17b), the respective Bs may be identical to or different from each other, and the respective Es may be identical to or different from each other.