Insertion time distribution. The histograms show the estimated insertion time distribution of roo and rooA (in red and blue bars, respectively), based on the intra-element LTR divergence. Notice the different scales on the y-axis. The vertical red and blue lines indicate the median insertion time in each genome for roo and rooA, respectively. Two roo elements of D. mojavensis had to be excluded because their LTR sequences were falsely identified. The histogram in the bottom right corner shows the insertion times of all roo and rooA elements. myr: million years.