Statistics in AtRTPrimer. Coverage of registered genes in AtRTPrimer is presented as the percent of registered genes with primer-pairs satisfying filtering conditions which are denoted as F1, F2, F2C, F2G, F3, F3C and F3G, respectively. (A) Here, the F1 filter has the same filtering condition applied to originally constructed AtRTPrimer database. We assume that there are possible amplicons from gDNA or similar cDNA so that we make the following filters: The F2 filter only includes registered genes with primer pairs producing amplicons from gDNA or similar cDNAs, whose sizes are not the same with that of a target gene. We assumed that the sizes of two amplicons are the same when they have the difference of less than five base pairs between each other. The F3 filter only includes registered genes with primer pairs producing no amplicons from both gDNA and similar cDNAs. The F2C and F3C filters have the same filtering conditions as F2 and F3, respectively, except for checking amplicons from only similar cDNAs. The F2G and F3G filters have the same filtering conditions as F2 and F3, respectively, except for considering amplicons from only gDNA. (B) The histograms for the number of registered genes with respect to the number of primer pairs at various filtering conditions are shown. The changes of average numbers are 1,868, 1,212 and 141 primer pairs at filters, F1, F2 and F3, respectively. In the histogram, the number of primer pairs in x-axis is binned with the bin size of 10, and the frequencies of registered genes with more than 1,050 primer pairs in y-axis are omitted.