A method for detecting at least one of at least one first target DNA sequence and at least one second target DNA sequence from a library of DNA sequences, wherein the first target DNA sequence differs from the second target DNA sequence in that a single or multiple nucleotide substitution or deletion or insertion in the second target sequence generates a restriction site for a restriction endonuclease, giving rise - if cleaved by the restriction endonuclease - to a first cleaved second target sequence 3' of the generated restriction site and a second cleaved second target sequence 5' of the generated restriction site, comprising the steps of: (a) providing the library of DNA sequences, each of the DNA sequences comprising, respectively from the 5' end to the 3' end, a first sequence segment having a length from 15 to 50 nucleotides, a second sequence segment of genomic DNA as cleaved by the restriction endonuclease, and a third sequence segment reverse complementary to the union of the first sequence segment and, if any, the 5' overhang generated by the restriction endonuclease; (b) amplifying the library of DNA sequences by PCR using: - at least one first reverse primer which hybridises to the 3' end region of the second sequence segment of the at least one first target sequence positive strand or at least one first cleaved second target sequence positive strand; - at least one second forward primer which hybridises to the 3' end region of the second sequence segment of the at least one first target sequence antipositive strand; - at least one third forward primer comprising a first 5' portion hybridising to the 5' end region of the third sequence segment of the at least one first cleaved second target sequence antipositive strand and a second 3' portion hybridising to the 3' end region of the second sequence segment of the at least one first cleaved second target sequence antipositive strand, wherein the first portion of the at least one third forward primer has a length from 20% to 80% with respect to the total length of the at least one third forward primer. (c) detecting DNA sequences amplified in step (b). (a) providing the library of DNA sequences, each of the DNA sequences comprising, respectively from the 5' end to the 3' end, a first sequence segment having a length from 15 to 50 nucleotides, a second sequence segment of genomic DNA as cleaved by the restriction endonuclease, and a third sequence segment reverse complementary to the union of the first sequence segment and, if any, the 5' overhang generated by the restriction endonuclease; (b) amplifying the library of DNA sequences by PCR using: - at least one first reverse primer which hybridises to the 3' end region of the second sequence segment of the at least one first target sequence positive strand or at least one first cleaved second target sequence positive strand; - at least one second forward primer which hybridises to the 3' end region of the second sequence segment of the at least one first target sequence antipositive strand; - at least one third forward primer comprising a first 5' portion hybridising to the 5' end region of the third sequence segment of the at least one first cleaved second target sequence antipositive strand and a second 3' portion hybridising to the 3' end region of the second sequence segment of the at least one first cleaved second target sequence antipositive strand, wherein the first portion of the at least one third forward primer has a length from 20% to 80% with respect to the total length of the at least one third forward primer. - at least one first reverse primer which hybridises to the 3' end region of the second sequence segment of the at least one first target sequence positive strand or at least one first cleaved second target sequence positive strand; - at least one second forward primer which hybridises to the 3' end region of the second sequence segment of the at least one first target sequence antipositive strand; - at least one third forward primer comprising a first 5' portion hybridising to the 5' end region of the third sequence segment of the at least one first cleaved second target sequence antipositive strand and a second 3' portion hybridising to the 3' end region of the second sequence segment of the at least one first cleaved second target sequence antipositive strand, wherein the first portion of the at least one third forward primer has a length from 20% to 80% with respect to the total length of the at least one third forward primer. (c) detecting DNA sequences amplified in step (b).