Fig. 1

Phylogenetic tree of Perissodactyla L1 families based on the longest non-recombining region of ORF2, including the reverse transcriptase and endonuclease domains. This tree was built using the maximum-likelihood method with the HKY + G model of a non-recombining region of ORF2 as depicted in the schematic diagram of an L1 element. To test the robustness of this tree, bootstrap values for 1000 replicates were calculated and are shown at each node. Red arrows depict the acquisition of new 5’UTR sequences