Methods for multiplex PCR

A method of multiplex PCR amplification of a specific target locus on a nucleic acid substrate for preparing a targeted next generation sequencing library comprising the steps of:

• (i) combining a plurality of target-specific primers with the nucleic acid substrate to yield a single polymerase chain reaction (PCR) reaction mixture, wherein the plurality of target-specific primers comprise a first forward primer, a second forward primer, a first reverse primer and a second reverse primer, wherein each of the first and second forward and reverse primers comprise a 3′ complementary sequence that is fully complementary to a sequence of the specific target locus and a 5′ noncomplementary sequence that is not complementary to a sequence of the nucleic acid substrate, wherein the 3′ complementary sequence for each of the first and second forward and reverse primers is different, wherein the 3′ complementary sequence is between 16 and 30 bases in length, and wherein the specific target locus is a gene known to have clinical relevance in oncology;
• (ii) subjecting the PCR reaction mixture to a multiplex polymerase chain reaction thereby generating at least three amplicons within the specific target locus, wherein the at least three amplicons comprise a first amplicon produced by the first forward primer and the first reverse primer, a second amplicon produced by the second forward primer and the second reverse primer, and a third amplicon produced by the second forward primer and the first reverse primer, wherein the third amplicon is shorter in length than the first and second amplicons, wherein at least a portion of the 5′ noncomplementary sequence of the second forward primer and the first reverse primer is the same such that each strand of the third amplicon comprises a 3′ sequence and a 5′ sequence that are complementary to each other, wherein the third amplicon possesses overlapping sequence with the first and second amplicons, wherein the first amplicon possesses overlapping sequence with the second amplicon, wherein when the third amplicon is denatured, each strand of the third amplicon forms a secondary structure as a result of the 3′ sequence being complementary to the 5′ sequence, wherein at the end of the multiplex polymerase chain reaction, the first and second amplicons are each present at a greater amount than the third amplicon, and wherein the nucleic acid substrate is human genomic DNA.

A method of multiplex PCR amplification of a specific target locus on a nucleic acid substrate for preparing a targeted next generation sequencing library comprising the steps of:

• (i) combining a plurality of target-specific primers with the nucleic acid substrate to yield a single polymerase chain reaction (PCR) reaction mixture, wherein the plurality of target-specific primers comprise a first forward primer, a second forward primer, a first reverse primer and a second reverse primer, wherein each of the first and second forward and reverse primers comprise a 3′ complementary sequence that is fully complementary to a sequence of the specific target locus and a 5′ noncomplementary sequence that is not complementary to a sequence of the nucleic acid substrate, wherein the 3′ complementary sequence for each of the first and second forward and reverse primers is different, wherein the 3′ complementary sequence is between 16 and 30 bases in length;
• (ii) subjecting the PCR reaction mixture to a multiplex polymerase chain reaction thereby generating at least three amplicons within the specific target locus, wherein the at least three amplicons comprise a first amplicon produced by the first forward primer and the first reverse primer, a second amplicon produced by the second forward primer and the second reverse primer, and a third amplicon produced by the second forward primer and the first reverse primer, wherein the third amplicon is shorter in length than the first and second amplicons, wherein at least a portion of the 5′ noncomplementary sequence of the second forward primer and the first reverse primer is the same such that each strand of the third amplicon comprises a 3′ sequence and a 5′ sequence that are complementary to each other, wherein the third amplicon possesses overlapping sequence with the first and second amplicons, wherein the first amplicon possesses overlapping sequence with the second amplicon, wherein when the third amplicon is denatured, each strand of the third amplicon forms a secondary structure as a result of the 3′ sequence being complementary to the 5′ sequence, wherein the secondary structure is stable during a primer annealing step of the multiplex polymerase chain reaction.