Adaptive evolution and structure modeling of rbcL gene in Ephedra

The adaptive evolution of the rbcL gene in 14 species of Ephedra and 9 other gymnosperms was tested by the PAML program. Three large-scale selections were found in the catalytic region of the RbcL protein by branch model. Species in Ephedra with positive selection at the 365th codon site in rbcL gene were detected by branch-site model. 3D structure modeling showed that the 365th codon could change the spatial structure of the β-sheet (βG, βH, or βE) of the RbcL protein. These changes may be associated with the adaptation of the protein in Ephedra to the environment.