Figure 7.
Divergence of EndA and tRNA genes in Archaea. tRNA genes are predicted for a total of 46 archaeal species that belong to five major groups: DPANN, Euryarchaeota, Stygia, Asgard and TACK. Classification of Clusters I and II, the Euryarchaeota and Stygia superclass, is as proposed by Adam et al. (62). Four types of EndAs (α4, α′2, (αβ)2 and ϵ2) and the relative ratio of the four types of disrupted tRNA genes are indicated: single intron located at the canonical position 37/38 (blue), single intron located at the non-canonical position (light blue), multiple introns (orange), split introns, and permuted introns (purple). The boxed number indicates the total number of predicted tRNA genes for each species. The insertion of the three major EndA-specific loops, formally known as CSL (L1), ASL (L2) and Nanoarchaea/ARMAN-2-specific loop (L3), are indicated.