Phylogeny of non-LTR elements based on their reverse transcriptase domain. Drosophila melanogaster non-LTR retrotransposons are shown in bold on the phylogenetic tree based on reverse transcriptase sequences . Sequence alignment was produced by CLUSTAL W software by adding Waldo, JuanDm and You sequences to the alignment DS36752 . Numbers at the nodes represent bootstrap values as percentages out of 500 replicates. The unrooted neighbor-joining tree and bootstrap analysis were inferred as implemented in the MEGA package .