Figure 6.

Neighbor-Joining trees for vertebrate ATRX with bootstrap and divergence time estimations. (A) Evolutionary relationships among ATRX homologs were inferred using the Neighbor-Joining method⁸⁷. The bootstrap consensus tree inferred from 10000 replicates is taken to represent the evolutionary history of the taxa analyzed⁸⁸. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (10000 replicates) are shown next to the branches⁸⁸. Evolutionary distances were computed using the Maximum Composite Likelihood method⁸⁹ and are in the units of the number of base substitutions per site. The analysis involved 13 nucleotide sequences. Codon positions included were 1st + 2nd + 3rd + Noncoding. All positions containing gaps and missing data were eliminated resulting in the inclusion of 251 positions in the final dataset. Evolutionary analyses were conducted in MEGA7⁸⁴. The newt represents sequence from Notophthalmus viridescens. (B) A time-scaled phylogenetic tree inferred using the Reltime method⁹⁰ and estimates of branch lengths inferred using the Neighbor-Joining method as in A⁸⁷. The tree was computed using 10 calibration constraints. Divergence times estimated by Timetree were added manually and are marked with gray arrows⁴⁹. This tree indicates that the duplication event giving rise to ATRW in axolotl may have occurred ~20MYA.