Fig. 1.

The HERV transcriptome in PBMCs. Percentages and absolute counts of positive signal-associated probesets within individual groups of the “HERV_prototypes” repertoire and HERV_Dfam and MaLR_Dfam repertoires. A probeset was included as reflecting a significant transcriptional activity if its normalised intensity was over an intensity threshold of 2^5.5 in at least 14 out of the 45 samples (for all conditions). This conservatory threshold was defined as the minimal intensity level shared by all repertoires that exhibited an acceptable variability, i.e. the 75th percentile of the distribution of the variation coefficient as a function of intensity should be lower than 10% (illustrated in Additional file 1: Figure S1). HERV prototype groups were grouped by retrovirus classes, namely gammaretrovirus (green), betaretrovirus (red) and spuma-epsilon like retrovirus (blue). The HERV and MaLR Dfam repertoires were each depicted as a global homogeneous entity (purple)