Format: ORAL

Flvia Fonseca Pezzini1, Moabe Ferreira Fernandes2,3, Rafaela Jorge Trad1, Gregory J. Kenicer1, Erik J. M. Koenen4, Jens J.Ringelberg4,Kyle G. Dexter4, Colin E. Hughes5, R. Toby Pennington1,2

1 Royal Botanic Garden Edinburgh, Edinburgh, United Kingdom 2 University of Exeter, Exeter, United Kingdom 3 Royal Botanic Gardens Kew, Surrey, United Kingdom 4 School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom 5 Department of Systematic and Evolutionary Botany, University of Zurich, Switzerland

Phylogenetic trees are fundamental for understanding the evolution of life on Earth, providing insights into the assembly of biotas, morphological trait shifts, and diversification dynamics. Recent advances in High-throughput sequencing (HTS) technologies are generating an explosion of DNA sequence data and prompting new approaches to enhance phylogenetic resolution. However, sparse sampling of species and intraspecific diversity remains an important limitation for global-scale comparative studies of large clades. Combining numerous species-level phylogenies which benefit from thoroughly curated taxonomy, dense taxon sampling and Sanger sequencing data, with more sparsely sampled higher-level backbone phylogenies presents a useful avenue for generating robust, densely sampled, well curated, time-calibrated phylogenetic metatrees or metachronograms. In this study we present a workflow to integrate large-scale sparsely sampled higher-level backbone trees with fine-scale, clade-specific densely sampled phylogenies. We demonstrate this approach for the species-rich legume subfamily Papilionoideae.We first produced a dated backbone using 20 fossil calibrations and a phylogeny containing 3696 tips representing 20% of known legume species (LPWG 2017). We then searched the literature for well sampled, thoroughly curated phylogenies built for specific Papilionoideae clades using both HTS or Sanger sequencing. When phylogenies were not available, we used the alignments or downloaded the accessions from GenBank to generate phylogenies using MrBayes. We checked ESS values, average standard deviation of split frequencies and whether the topology matched the one in the original study. Those fine-scale phylogenies were then grafted onto the backbone to produce a meta-chronogram. This approach means that diverse data types can be combined to build a single phylogeny, thereby tapping into the full wealth of available DNA sequence data and maximising the number of taxa that can be sampled withmolecular data, and provides a computationally tractable way to build a large phylogeny with many taxa.