Diversity and expression patterns of LTR retroelements in the frog genome and transcriptomes. (a) Diversity of LTR REs in the genome of Silurana and in the frogs transcriptomes analyzed. (b) Number of LTR RE copies in the Silurana genome; (c) Proliferation patterns based on average relatedness of LTR REs in the Silurana genome. The average relatedness was calculated on the basis of amino acids as LOG (∑ (Alignment coverage *Alignment score)), in which a higher relatedness score indicates that the elements within that group are closer related to one another. (d) Arithmetic means of relative NRC values calculated for brain (B), heart (H), liver (L), and muscle (M) of S. tropicalis (left points) and P. lessonae (right points). (e) Relative amount of LTR REs in different frog transcriptomes.