Expression maps of differentially expressed TEs. Differentially expressed portions of TEs are shown with respect to their location in the element consensus sequence; the y-axis shows the log2 ratio of signals between the indicated tissue type and the pool of tissues, and the x-axis shows the corresponding position in the TE. A) An ERV2 member, IAPEY4_I is variably abundant in heart. IAPEY4 LTR sequences (which are separate Repbase entries) were added to proviral sequences for a complete depiction of the element. Annotation of the functional domains gag, pol and env were made based on Blastx alignments to Mtv1; darker hues of a given color indicate a higher percent identity of similarity to the exogenous virus. The annotation of (b) and (c) are similar; (d) is a long terminal repeat (LTR) of an endogenous retrovirus with no ORFs. B) ERVB4_1B, another endogenous retrovirus, shows testis specific segmental expression. C) IAPLTR3 also an ERV2 shows segmental transcript abundance in testis as well. D) RLTR1D2 is an ERV1 long terminal repeat which shows differential transcript abundance in kidney. E) B1 SINE is a non-autonomous and non- LTR TE which does not show highly tissue specific abundance. F) LINE-1 or L1, an autonomous, non-LTR TE without a highly tissue specific abundance.