Phylogenetic inference in section Archerythroxylum informs taxonomy, biogeography, and the domestication of coca (Erythroxylum species)

This investigation establishes the first sequence-based phylogenetic hypothesis of species relationships in the Coca family (Erythroxylaceae). We focused our phylogenomic inference on the largest taxonomic section in the genus Erythroxylum (Archerythroxylum O. E. Schulz) using concatenation and gene tree reconciliation methods from hybridization-based target capture of 427 genes. We show that Neotropical Erythroxylum are monophyletic within the Paleotropical lineages, yet Archerythroxylum and all of the other taxonomic sections from which we sampled multiple species lack monophyly. We mapped phytogeographic states onto the tree and found some concordance between these regions and clades. The wild species E. gracilipes and E. cataractarum are most closely related to the cultivated E. coca and E. novogranatense but relationships within this “coca” clade remain equivocal, suggesting a more complicated origin than Plowman’s single-domestication hypothesis. Our results point to the difficult...