Synteny conservation and duplication dating of MIR168 paralogs. A) Synteny conservation of the genomic regions encompassing MIR168a and MIR168b in A. thaliana and P. trichocarpa. Arrows represent MIR168a and MIR168b; the squares represent coding genes with at least one homolog in both genomes; the black lines represent RBMs and the gray lines connect BLASTP hits with lower homology within the same syntenic regions. Dashed lines connect At4g19410 homologs; diagonal lines on Ptc_LG_III represent a 7 Mbp long region not syntenic to Arabidopsis. B) Phylogenetic reconstruction of At4g19410 homologs in the Arabidopsis and poplar genomes. The portion of the linearized tree representing the homologs of At4g19410 located in the same genomic regions as MIR168a and MIR168b is highlighted in black. Values at the branch roots correspond to majority rule consensus bootstrap values ≥ 50%. Ath: A. thaliana; Ptc: P. trichocarpa; Ks: number of synonymous nucleotide substitutions per synonymous site.