title: How to handle speciose clades? Mass taxon-sampling as a strategy towards illuminating the natural history of Campanula (Campanuloideae).
abstract: BACKGROUND
  Speciose clades usually harbor species with a broad spectrum of adaptive strategies and complex distribution patterns, and thus constitute ideal systems to disentangle biotic and abiotic causes underlying species diversification. The delimitation of such study systems to test evolutionary hypotheses is difficult because they often rely on artificial genus concepts as starting points. One of the most prominent examples is the bellflower genus Campanula with some 420 species, but up to 600 species when including all lineages to which Campanula is paraphyletic. We generated a large alignment of petD group II intron sequences to include more than 70% of described species as a reference. By comparison with partial data sets we could then assess the impact of selective taxon sampling strategies on phylogenetic reconstruction and subsequent evolutionary conclusions.
  
  
  RESULTS
  Phylogenetic analyses based on maximum parsimony (PAUP, PRAP), Bayesian inference (MrBayes), and maximum likelihood (RAxML) were first carried out on the large reference data set (D680). Parameters including tree topology, branch support, and age estimates, were then compared to those obtained from smaller data sets resulting from "classification-guided" (D088) and "phylogeny-guided sampling" (D101). Analyses of D088 failed to fully recover the phylogenetic diversity in Campanula, whereas D101 inferred significantly different branch support and age estimates.
  
  
  CONCLUSIONS
  A short genomic region with high phylogenetic utility allowed us to easily generate a comprehensive phylogenetic framework for the speciose Campanula clade. Our approach recovered 17 well-supported and circumscribed sub-lineages. Knowing these will be instrumental for developing more specific evolutionary hypotheses and guide future research, we highlight the predictive value of a mass taxon-sampling strategy as a first essential step towards illuminating the detailed evolutionary history of diverse clades.
authors.affiliation: Botanischer Garten und Botanisches Museum, Freie Universität Berlin, Berlin, Germany. g.mansion@bgbm.org
authors.forename: Guilhem
authors.initials: G
authors.lastname: Mansion
authors.forename: Gerald
authors.initials: G
authors.lastname: Parolly
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Crowl
authors.forename: Evgeny
authors.initials: E
authors.lastname: Mavrodiev
authors.forename: Nico
authors.initials: N
authors.lastname: Cellinese
authors.forename: Marine
authors.initials: M
authors.lastname: Oganesian
authors.forename: Katharina
authors.initials: K
authors.lastname: Fraunhofer
authors.forename: Georgia
authors.initials: G
authors.lastname: Kamari
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Phitos
authors.forename: Rosemarie
authors.initials: R
authors.lastname: Haberle
authors.forename: Galip
authors.initials: G
authors.lastname: Akaydin
authors.forename: Nursel
authors.initials: N
authors.lastname: Ikinci
authors.forename: Thomas
authors.initials: T
authors.lastname: Raus
authors.forename: Thomas
authors.initials: T
authors.lastname: Borsch
mesh_terms: D001499:Bayes Theorem; D029422:Campanulaceae / Q000235:genetics*; D002965:Classification / Q000379:methods*; D018744:DNA, Plant / Q000235:genetics; D019143:Evolution, Molecular; D007438:Introns; D016013:Likelihood Functions; D008954:Models, Biological; D008957:Models, Genetic; D008967:Molecular Biology; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D018744:DNA, Plant