title: AFLP markers provide insights into the evolutionary relationships and diversification of New Caledonian Araucaria species (Araucariaceae).
abstract: OBJECTIVE
  Despite its small size, New Caledonia is characterized by a very diverse flora and striking environmental gradients, which make it an ideal setting to study species diversification. Thirteen of the 19 Araucaria species are endemic to the territory and form a monophyletic group, but patterns and processes that lead to such a high species richness are largely unexplored.
  
  
  METHODS
  We used 142 polymorphic AFLP markers and performed analyses based on Bayesian clustering algorithms, genetic distances, and cladistics on 71 samples representing all New Caledonian Araucaria species. We examined correlations between the inferred evolutionary relationships and shared morphological, ecological, or geographic parameters among species, to investigate evolutionary processes that may have driven speciation.
  
  
  RESULTS
  We showed that genetic divergence among the present New Caledonian Araucaria species is low, suggesting recent diversification rather than pre-existence on Gondwana. We identified three genetic groups that included small-leaved, large-leaved, and coastal species, but detected no association with soil preference, ecological habitat, or rainfall. The observed patterns suggested that speciation events resulted from both differential adaptation and vicariance. Last, we hypothesize that speciation is ongoing and/or there are cryptic species in some genetically (sometimes also morphologically) divergent populations.
  
  
  CONCLUSIONS
  Further data are required to provide better resolution and understanding of the diversification of New Caledonian Araucaria species. Nevertheless, our study allowed insights into their evolutionary relationships and provides a framework for future investigations on the evolution of this emblematic group of plants in one of the world's biodiversity hotspots.
authors.affiliation: Muséum National d'Histoire Naturelle, UMR CNRS 'Origine, Structure et Evolution de la Biodiversité', Paris, France. gaudeul@mnhn.fr
authors.forename: Myriam
authors.initials: M
authors.lastname: Gaudeul
authors.forename: Germinal
authors.initials: G
authors.lastname: Rouhan
authors.forename: Martin F
authors.initials: MF
authors.lastname: Gardner
authors.forename: Peter M
authors.initials: PM
authors.lastname: Hollingsworth
mesh_terms: D000222:Adaptation, Physiological; D000531:Altitude; D054458:Amplified Fragment Length Polymorphism Analysis; D001499:Bayes Theorem; D005075:Biological Evolution; D016000:Cluster Analysis; D018744:DNA, Plant / Q000235:genetics; D004463:Ecology; D017753:Ecosystem; D005819:Genetic Markers / Q000235:genetics; D049810:Genetic Speciation; D014644:Genetic Variation; D005843:Geography; D009510:New Caledonia; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D011110:Polymorphism, Genetic; D064028:Tracheophyta / Q000235:genetics* / Q000254:growth & development / Q000502:physiology
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers