title: Molecular phylogenetic analysis of the Persea group (Lauraceae) and its biogeographic implications on the evolution of tropical and subtropical Amphi-Pacific disjunctions.
abstract: OBJECTIVE
  The Persea group (Lauraceae) has a tropical and subtropical amphi-pacific disjunct distribution with most of its members, and it includes two Macaronesian species. The relationships within the group are still controversial, and its intercontinental disjunction has not been investigated with extensive sampling and precise time dating. •
  
  
  METHODS
  ITS and LEAFY intron II sequences of 78 Persea group species and nine other Lauraceae species were analyzed with maximum parsimony and Bayesian inference. Divergence time estimation employed Bayesian Markov chain Monte Carlo method under a relaxed clock. •
  
  
  RESULTS
  Several traditional genera or subgenera within the Persea group form well-supported monophyletic groups except Alseodaphne and Dehaasia. The divergence time of the Persea group is estimated as ∼55.3 (95% higher posterior densities [HPD] 41.4-69.9) million years ago (mya). Two major divergences within the Persea group are estimated as ∼51.9 (95% HPD 38.9-63.9) mya and ∼48.5 (95% HPD 35.9-59.9) mya. •
  
  
  CONCLUSIONS
  Persea can be retained as a genus by the inclusion of Apollonias barbujana and exclusion a few species that do not fit into the established subgenera. A major revision is recommended for the delimitation between Alseodaphne, Dehaasia, and Nothaphoebe. We suggest that the Persea group originated from the Perseeae-Laureae radiation in early Eocene Laurasia. Its amphi-pacific disjunction results from the disruption of boreotropical flora by climatic cooling during the mid- to late Eocene. The American-Macaronesian disjunction may be explained by the long-distance dispersal.
authors.affiliation: Laboratory of Plant Phylogenetics and Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, P. R. China.
authors.forename: Lang
authors.initials: L
authors.lastname: Li
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Jens G
authors.initials: JG
authors.lastname: Rohwer
authors.forename: Henk
authors.initials: H
authors.lastname: van der Werff
authors.forename: Zhi-Hua
authors.initials: ZH
authors.lastname: Wang
authors.forename: Hsi-Wen
authors.initials: HW
authors.lastname: Li
mesh_terms: D001483:Base Sequence; D001499:Bayes Theorem; D002138:Calibration; D017931:DNA Primers; D005843:Geography; D019770:Lauraceae / Q000145:classification / Q000235:genetics*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D014329:Tropical Climate
chemical_list: D017931:DNA Primers