Abstract: The present invention provides a method for amplifying a specific target nucleic acid sequence. The method comprises (1) forming a reaction mixture comprising: (i) the target sequence; (ii) primers comprising a first primer at least a portion of which at the 3′ end thereof is substantially complementary to a first segment at a first end of the target sequence, a second primer at least a portion of which at the 5′ end thereof is substantially complementary to a second segment at a second end of the target sequence, the 5′ end of the second primer being adjacent the 3′ end of the first primer, and a third primer, the third primer being substantially complementary to a segment of the second primer at the 3′ end thereof; (iii) at least four different nucleotide bases; (iv) thermostable polymerase and thermostable ligase; and (2) thermocycling the reaction mixture.