Ancient allopatry and ecological divergence act together to promote plant diversity in mountainous regions: evidence from comparative phylogeography of two endemic genera in the Sino-Himalayan region

Finding out shared divergence pattern among different plant groups is crucial to understanding the origin of plant diversity in mountain regions. In this study, we chose two endemic genera in the Sino-Himalayan region: Megacodon and Beesia, which both have very few species and exhibit a fragmented distribution pattern. This study aims to understand their divergence processes and summarize shared speciation or divergence patterns in this region.Using ddRAD-seq, chloroplast genome, and molecular fragments, we studied phylogenetic relationships, population structure, and historical biogeography of Beesia and Megacodon. For Beesia, we further used morphological measurement and RNA-seq to investigate its adaptive divergence along an altitudinal gradient.