Fig. 4
The results of evolutional analysis of protein-coding genes in Dendrobium. A Comparison of non-synonymous (dn) and synonymous (ds) substitution rates among three photosynthetic pathways (C3, CAM and C3-CAM). The substitutions rates were calculated for the whole chloroplast genome with B. inconspicuum as reference. Of note, the chloroplast genomes of Dendrobium among three photosynthetic pathways revealed various substitution rates in their protein-coding sequences; B ML tree with adaptive selection genes in different branches among Dendrobium species, respectively. Different colors are used to mark different branches