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Summary The tree of life is riddled with reticulate evolutionary histories, and some clades, such as the eastern standingPhlox, appear to be hotspots of hybridization. In this group, there are two cases of reinforcement and nine hypothesized hybrid species. Given their historical importance in our understanding of plant speciation, the relationships between these taxa and the role of hybridization in their diversification require genomic validation.Using phylogenomic analyses, we resolve the evolutionary relationships of the eastern standingPhloxand evaluate hypotheses about whether and how hybridization and gene flow played a role in their diversification.Our results provide novel resolution of the phylogenetic relationships in this group, including paraphyly across some taxa. We identify gene flow during one case of reinforcement and find genomic support for a hybrid lineage underlying one of the five hypothesized homoploid hybrid speciation events. Additionally, we estimate the ancestries of four allotetraploid hybrid species.Our results are consistent with hybridization contributing to diverse evolutionary outcomes within this group; although, not as extensively as previously hypothesized. This study demonstrates the importance of phylogenomics in evaluating hypothesized evolutionary histories of non‐model systems and adds to the growing support of interspecific genetic exchange in the generation of biodiversity.
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This content will become publicly available on May 1, 2027
Geography and admixture shape the genome‐scale phylogeny of North American Delphinium
Summary The genusDelphiniumexemplifies the complexity of plant diversification in mountainous regions, where rapid speciation, hybridization, and morphological convergence frequently obscure species boundaries. The North American lineageDelphiniumsect.Diedropetalahas rapidly radiated across a range of ecological habitats, from alpine tundra to desert grasslands, forming an iconic component of western wild flower communities.Here, we present a genome‐scale phylogeny of 34 taxa using ddRAD‐seq data from 150 individuals sampled across their geographic ranges.Our results reveal strong phylogenetic structure corresponding to biogeographic regions, including several well‐supported clades that cut across existing taxonomic subsections, emphasizing the need for taxonomic revision. Hybridization and introgression are widespread, occurring both within and between these regional clades. Most species are connected through a syngameon‐like network of introgression, with few widespread species acting as central hubs. We describe six higher‐level clade names and use an agent‐based artificial intelligence analysis to identify morphological synapomorphies that align with our genomic findings.Our study demonstrates that geography and gene flow have played a dominant role in shaping the evolutionary history ofDelphiniumin North America, offering a framework for revising its taxonomy and informing future conservation efforts.
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- Award ID(s):
- 2046813
- PAR ID:
- 10685246
- Publisher / Repository:
- New Phytologist
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 250
- Issue:
- 3
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- 1934 to 1947
- Subject(s) / Keyword(s):
- Alpine, biogeography, hybridization, Larkspur, plant, RAD-seq, Syngameon
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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