A Commotion Occurred In Amplification Of Consecutive Polymerase Chain Reaction (PCR): The Mechanism And Implications

Because of its high efficiency, polymerase chain reaction (PCR) has been used in each branch of biological science since its invention about 20 years ago, including sequence amplification, artificial mutation heritable disease diagnosis, forensic detection, gene expression analysis, and so on. However, it is still common and serious in how to improve the specificity and to obtain pure desired sequence by PCR. Different PCR variants or special treatments were modified to enhance its specificity, such as hot-start, touch-down, nest primers, addition of beneficial chemicals, and so on. For special aims, multiple PCR, reverse PCR, quantitative PCR, in situ PCR, as well as capillary PCR, were developed. Additionally, many kinds of genotyping and molecular marking techniques, such as RAPD, AFLP, SSR, ISSR, SNP, etc., have accelerated genetic analysis and construction of genetic maps. After 20 years, researchers are still concerning on how to improve PCR, to develop new PCR variants and to explore more extensive application.Various abnormal phenomena have been observed during PCR so far. Those included failure of amplification (no product), low specificity (product was mixture of expected products with the unexpected), low efficiency of amplification, primers self-ligation and self-amplification, and so on. Another kind of abnormal phenomena involves...