Strand bias of TE transcripts. A) Bar plot showing the sense strand bias of TE expression. Total raw signal intensities of TE probes are plotted for sense and antisense orientations. B) An ERV2 member, IAPEY4_I is segementally expressed in the sense strand in heart. Corresponding antisense probes show no differential expression across tissues. The Y-axis of this plot shows the log2 ratio value and the X-axis shows positions of the probe with reference to the element sequence. C) Heatmap of sense versus antisense experiments of testis, lung, and breast. The X-axis represents the mouse TE families ordered by type (blue for ERVs, orange for L1s, red for SINEs and purple for all other families). The mean M value (log2 ratio) of all probes is assigned to each family is shown, the values of which range between -4 and 4.