Lycophyte transcriptomes reveal two whole-genome duplications in Lycopodiaceae: Insights into the polyploidization of

Lycophytes are an ancient clade of the non-flowering vascular plants with chromosome numbers that vary from tens to hundreds. They are an excellent study system for examining whole-genome duplications (WGDs), or polyploidization, in spore-dispersed vascular plants. However, a lack of genome sequence data limits the reliable detection of very ancient WGDs, small-scale duplications (SSDs), and recent WGDs. Here, we integrated phylogenomic analysis and the distribution of synonymous substitutions per synonymous sites (Ks) of the transcriptomes of 13 species of lycophytes to identify, locate, and date multiple WGDs in the lycophyte family Lycopodiaceae. Additionally, we examined the genus