Mix 2 targets sequences between the framework 1 (FR1) and joining (JH) regions. The resulting amplicons include a portion of the FR1 region to the downstream JH region. The primers that target the VHL and FR1 regions have been redesigned to include a universal sequencing tag at the 5'end. This new design allows for bi-directional sequencing of clonal PCR products with just one sequencing-tag specific forward primer and one JH reverse primer, thus ensuring a more reliable and complete coverage of clonal products.