Transposable Element Activity Is Associated With the Rise of Termite Diversity

Transposable elements (TEs) have long been hypothesized as a driver of lineage diversification due to their mutagenic ability. However, the correlation between rates of TE activity and diversification has rarely been tested, since it is challenging to measure the rate of TE activity in the deep past. Here, we investigated TE activity during the last ~150 million years of termite evolution. First, we determined the timing of TE amplification events using the sequence divergence of TE copies and identified two waves of TE bursts that took place synchronously across termite lineages, coinciding with the two major phases of termite diversification. Furthermore, we built phylogenetic trees using the presence/absence of orthologous TE insertions in the flanking regions of Ultraconserved Elements (UCEs), in which the branch length provided a measure of the rate of TE insertion/deletion near UCEs along the termite phylogenetic tree. The rate of TE insertion/deletion near UCEs predicted up to 34.8% of the variation in the termite net diversification rate. Overall, these results supported TEs as an important contributor to species diversification. More broadly, this study provided a phylogenomic approach to quantify TE activity in the deep past.