The article discusses a method called "Touchdown PCR" to address the issue of spurious priming during gene amplification, particularly in complex genomes. The authors, R.H.Don, P.T.Cox, B.J.Wainwright, K.Baker, and J.S.Mattick, from the Centre for Molecular Biology and Biotechnology at the University of Queensland, propose a solution that begins at or above the expected annealing temperature and gradually decreases it by 1°C per cycle until a "touchdown" temperature is reached. This approach leverages the exponential nature of PCR reactions, where a 5°C difference in Tm can provide a 45-fold advantage to the correct product. The method was tested on amplifying cDNA sequences coding for leukemia inhibitory factor (LIF), where standard PCR conditions yielded spurious small bands. However, the touchdown PCR successfully amplified the correct LIF cDNA sequence, demonstrating its effectiveness in bypassing spurious amplifications without lengthy optimization. The authors suggest that this method can be widely applied to similar situations, avoiding secondary problems such as temperature inconsistencies in thermal cycling machines.The article discusses a method called "Touchdown PCR" to address the issue of spurious priming during gene amplification, particularly in complex genomes. The authors, R.H.Don, P.T.Cox, B.J.Wainwright, K.Baker, and J.S.Mattick, from the Centre for Molecular Biology and Biotechnology at the University of Queensland, propose a solution that begins at or above the expected annealing temperature and gradually decreases it by 1°C per cycle until a "touchdown" temperature is reached. This approach leverages the exponential nature of PCR reactions, where a 5°C difference in Tm can provide a 45-fold advantage to the correct product. The method was tested on amplifying cDNA sequences coding for leukemia inhibitory factor (LIF), where standard PCR conditions yielded spurious small bands. However, the touchdown PCR successfully amplified the correct LIF cDNA sequence, demonstrating its effectiveness in bypassing spurious amplifications without lengthy optimization. The authors suggest that this method can be widely applied to similar situations, avoiding secondary problems such as temperature inconsistencies in thermal cycling machines.