Experimental design highlighting vernalization procedure. The experimental design was made in two steps (i) to investigate differences in DNA methylation between vernalized and non vernalized plants at the 4th leaf stage, and (ii) to investigate the mitotic and transgenerational inheritance of the DNA methylation signal. In these two sets of experiment, comparison of the VRN-A1 DNA methylation profile was performed for vernalized and non vernalized plants at the 4th leaf stage, thus allowing to check for repeatability of the signal (two independent sets of experiment). For each experiment and each stage (4th leaf, flag leaf, progeny 4th leaf), 3 independent plants were analyzed, as shown by the “x3” sign. Stages and type of leaf sampled are shown at the bottom each plant analyzed, in bold. Growing conditions are represented by blue (vernalization chamber) and green (greenhouse) lines, with length corresponding to the number of days on which the treatment was applied. Abbreviations: NV: non vernalized, V: vernalized, d: day.