Differences among the published ligation protocols. For each method, a temperature (y-axis) × time diagram (x-axis) is shown as it was used in the indicated references. LPA: Ligation-dependent Probe Amplification, DTM: Dual Tag Microarray, PPLMD: Padlock Probe Ligation in combination with Microarray Detection. *PPLMD II: Edwards et al.  did not use any abbreviated protocol name for their method contrary to the other authors [8, 12, 15, 17], but for clarity this protocol was called PPLMD II in this article.