PT - JOURNAL ARTICLE AU - Benjamin J. Cooper AU - Michael J. Moore AU - Norman A. Douglas AU - Warren L. Wagner AU - Matthew G. Johnson AU - Rick P. Overson AU - Angela J. McDonnell AU - Jeremie B. Fant AU - Krissa A. Skogen AU - Norman J. Wickett TI - Target enrichment and extensive population sampling help untangle the recent, rapid radiation of <em>Oenothera</em> sect. <em>Calylophus</em> AID - 10.1101/2021.02.20.432097 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.02.20.432097 4099 - http://biorxiv.org/content/early/2021/02/20/2021.02.20.432097.short 4100 - http://biorxiv.org/content/early/2021/02/20/2021.02.20.432097.full AB - Oenothera sect. Calylophus is a North American group of 13 recognized taxa in the evening primrose family (Onagraceae) with an evolutionary history that may include independent origins of bee pollination, edaphic endemism, and permanent translocation heterozygosity. Like other groups that radiated relatively recently and rapidly, taxon boundaries within Oenothera sect. Calylophus have remained challenging to circumscribe. In this study, we used target enrichment, flanking non-coding regions, summary coalescent methods, tests for gene flow modified for target-enrichment data, and morphometric analysis to reconstruct phylogenetic hypotheses, evaluate current taxon circumscriptions, and examine character evolution in Oenothera sect. Calylophus. Because sect. Calylophus comprises a clade with a relatively restricted geographic range, we were able to comprehensively sample across the range of geographic and morphological diversity in the group with extensive sampling. We found that the combination of exons and flanking non-coding regions led to improved support for species relationships. We reconstructed potential hybrid origins of some accessions and note that if processes such as hybridization are not taken into account, the number of inferred evolutionary transitions may be artificially inflated. We recovered strong evidence for multiple origins of the evolution of bee pollination from the ancestral hawkmoth pollination, the evolution of edaphic specialization on gypsum, and permanent translocation heterozygosity. This study applies newly emerging techniques alongside dense infraspecific sampling and morphological analyses to effectively address a relatively common but recalcitrant problem in evolutionary biology.Competing Interest StatementThe authors have declared no competing interest.