Relative levels of transcripts 3' of different categories of HERV-W elements as determined by real-time PCR. Levels of transcripts 3' of; intronic proviral elements, pseudoelements and solo LTRs are shown relative to expression-levels of their corresponding genes (i.e. ΔCt-values). Elements integrated on the sense (S) or anti-sense (AS) strand were analyzed separately. Statistical significance is indicated by **= p < 0.01, ***= p < 0.001.