I want to study the evolution of plant secondary metabolite evolution in medicinally important plant taxa. Recently I came across a paper which I am attaching at the end of this mail where the relation of phylogeny with the evolution of plant secondary metabolite has been elucidated convincingly. Now, if I want to study at gene expression level which controls the synthesis of the target molecule in the desired plant taxa, how should I proceed? How it is related to the phylogeny of a family?