Phylogenetic analysis
The phylogenetic relationships between Chinese flowering cabbage and other Brassica plants were analyzed using the orthologs from single-copy genes. The Orthofinder package was used to find orthogroups and single-copy genes. All of the single-copy genes in one species were concatenated into a super alignment, then run through multiple sequence alignment using the mafft program(Katoh & Toh, 2010). Easyspecietree (https://github.com/Davey1220/EasySpeciesTree) was used to generate the phylogenetic relationship between the species using the maximum likelihood method.