Data sources
We downloaded all of the genomic data and gene annotation data (gff3) of two green algae genomes (C. reinhardtii and C. subellipsoidea) from the Joint Genome Institute, four plant genomes (O. sativa, Z. mays, V. vinifera, and A. thaliana) from the Ensembl genome database, two plant genomes (G. max and S. bicolor) from the Plant Genome Database, and the B. rapa genome and annotation information data, available online from the B. rapa Database. We also collected each mitochondrial genome sequence from the National Center for Biotechnology Information (NCBI). All these data sources are summarized in Table 1.