Insertion of a reamplification round into the ISSR-PCR protocol gives new flax fingerprinting patterns

We expanded the basic ISSR-PCR protocol by an additional PCR reamplification round in order to detect whether increased PCR productivity would give new bands in ISSR patterns. We found that the reamplification step had a prominent impact on the quality of the inter-simple-sequence repeat (ISSR) PCR patterns of flax, depending on the particular primer used for PCR amplification. We could clearly distinguish between two types of reamplification effect. Most ISSR primers (16 out of 21) gave no reamplification effect as usual, but five primers (23.8%) provided a new ISSR fingerprinting pattern after the 2nd reamplification round, leaving the previous 1st round pattern completely blank. Therefore, we recommend the expansion of a basic ISSR-PCR protocol for another reamplification round in order to mine out full the fingerprinting potential from ISSR-PCR method.