Genomic DNA from leukocytes was pretreated in water (Water), long-range PCR buffer from Supplier A (Standard buffer), or QIAGEN LongRange PCR Buffer (LongRange Buffer), and then directly used for PCR (–) or incubated at 95°C (+) before PCR. Amplification reactions (50 μl) were performed using the QIAGEN LongRange PCR Kit. M: marker. Pretreatment of DNA in QIAGEN LongRange PCR Buffer provided protection from damage, resulting in increased yield. Reduced product yields were achieved due to greater DNA damage when DNA was pretreated in water or standard long-range PCR buffers.
Long PCR products (27 kb and 24 kb) were amplified from human genomic DNA using the QIAGEN LongRange PCR Kit and 2 additional long-range PCR kits from the indicated suppliers, according to the manufacturer's instructions. The QIAGEN LongRange PCR Kit provided much higher yields of specific product than the other kits that were tested.