Specific size-classes vd-sRNAs may largely prevail at certain genomic positions.

Histograms comparing location of the 5′ termini, frequency and size distribution of (−) vd-sRNAs corresponding to the HSVd hotspot 3 (HS3) and recovered from the different grapevine tissues. Numbers are referred to HSVd sequence variant with the accession number X06873. 5′→3′ orientation is from right to left.