Fig. 2From: Variation in base composition underlies functional and evolutionary divergence in non-LTR retrotransposonsPhylogenetic relationships among L1 elements based on the entire ORF2. The base composition of each element is shown above the tree. The tree was built with the maximum likelihood method using the LG + G + I + F model of mutation and its robustness was assessed by 500 bootstrap replicates. The tree was rooted using Tx1 elements. Nodes that are supported by bootstrap values higher than 70% are indicated with an asteriskBack to article page