Genome Skimming Resolves Clematis Evolutionary Relationships

Known as the "Queen of Climbers," the genus Clematis boasts over 300 species widely distributed across the globe. From tropical rainforests to sub-arctic regions, these plants are celebrated by gardeners for their vibrant flowers and are valued in traditional medicine. Despite their great popularity, however, scientists have long struggled to organize Clematis' rapid species radiation into a coherent family tree of Clematis has plagued taxonomists-a challenge that has persisted since Linnaeus first described the genus in 1753,

"Previous attempts using traditional DNA sequencing methods often failed to provide clear answers, frequently resulting in conflicting evolutionary trees based on whether nuclear or plastid (chloroplast) DNA was used," explains co-corresponding of a new study in Plant Diversity, Prof. Xie Lei from the State Key Laboratory of Efficient Production of Forest Resources at Beijing Forestry University. "Reconstructing a reliable phylogenetic framework for plant groups with rapid species radiation remains one of the most significant challenges in exploring the tree of life.

To that end, through the study, Xie and his colleagues presented the first comprehensive sectional classification for Clematis based on robust phylogenomic evidence.

"We incorporated 198 samples representing 151 species from around the world by moving beyond traditional methods to employ a "genome skimming" approach to assemble large datasets of nuclear single nucleotide polymorphisms (SNPs)" shares Xie.

The researchers found that nuclear SNP data provided a much clearer picture of the genus's history than previous methods.

Our results establish a framework for future studies on the evolution, ecology, and horticultural potential of this globally significant genus."  

Prof. Xie Lei, State Key Laboratory of Efficient Production of Forest Resources, Beijing Forestry University

The new analysis identified 22 well-supported evolutionary clades, leading the researchers to revise the infrageneric taxonomy into 22 distinct sections. "Our findings confirmed that many previously recognized subgenera were artificial groupings that did not reflect true evolutionary history," says Xie. "Additionally, the researchers traced the evolution of 12 key morphological characters, such as seedling shape and flower orientation, finding that many of these traits evolved independently multiple times."

By integrating multidisciplinary data, The team has resolved long-standing taxonomic ambiguities. This updated framework will be essential for breeders and botanists seeking to understand and utilize the immense diversity of Clematis.