Hybridization and Polyploidization Drive Diversification in Lappula, Study Reveals

A recent study led by Prof. LI Wenjun from the Xinjiang Institute of Ecology and Geography of the Chinese Academy of Sciences, has shed light on the evolutionary mechanisms underpinning the diversification of the genus Lappula. The findings were published in Molecular Phylogenetics and Evolution.

Lappula, a genus within the Boraginaceae family, is considered one of the most taxonomically complex groups within its family. Predominantly found in the mountainous and arid regions of Central Asia, the genus's taxonomic boundaries and infrageneric classification have long been unresolved, with notable discrepancies in species diversity.

Based on complete chloroplast genomes and 475 single-copy nuclear genes from 76 specimens across Central Asia, the researchers conducted phylogenomic analyses and revealed that Lappula, as currently defined, is not a monophyletic group. 

The study clarifies the evolutionary relationships between Lappula and related genera such as Lepechiniella, Rochelia, and Pseudolappula. The observed incongruence between gene trees and the species tree was attributed to incomplete lineage sorting and hybridization events.

Phylogenetic network analyses indicated that two highly species-rich lineages within Lappula—Clades IV and VII—originated through hybridization, with the tetraploids in Clades IV arising from two independent hybridization events. "The findings underscore the significant roles that hybridization and polyploidization have played in driving the genus's evolutionary diversification," said LIU Danhui, first author of the study.

This study provides a phylogenetic framework for Lappula and highlights the complex evolutionary processes that shape plant biodiversity in Central Asia.

Read the full article: https://doi.org/10.1016/j.ympev.2025.108361

Contact

LONG Huaping

Xinjiang Institute of Ecology and Geography

E-mail: longhp@ms.xjb.ac.cn

Web: http://english.egi.cas.cn