Separation of LTR elements in different classes for each genome. For each genome that contains BEL/Pao elements, we show the abundance of BEL/Pao, Ty1/Copia, Ty3/Gypsy and DIRS elements, based on our classification. The horizontal axis indicates the relative abundance of each element class in each genome, normalized to the interval (0,1). The difference in the length of each bar to the frequency of one reflects unclassified transposable elements. Their frequency is quite large in some genomes. The three most abundant phyla in our data set (arthropods, nematodes, chordates) are labeled.