*4.3. Identification of Orthologous Genes*

Datasets for three kinds of *Dendrobium* species were obtained from the NCBI Sequence Read Archive (SRA) (https://www.ncbi.nlm.nih.gov/sra) with accessing number SRP122499, SRP139000, and SRP150489. There was a total of 27 samples of *Dendrobium* that were taken from three different species (*Dendrobium huoshanense*, *Dendrobium o*ffi*cinale,* and *Dendrobium moniliforme*) and three different tissues (stems, leaves, and roots). The data for these samples were submitted by our own laboratory. The OrthoMCL pipeline [54] was used with standard settings to identify potential orthologous genes in *Dendrobium*, and subsequently aligned using the MUSCLE algorithm [55].
