title: The evolution of substrate differentiation in Minuartia series Laricifoliae (Caryophyllaceae) in the European Alps: In situ origin or repeated colonization?
abstract: OBJECTIVE
  Substrate specialization is often considered an important factor in evolutionary diversification. A classic example of divergence related to different substrate types is the dichotomy between calcicole and calcifuge plants on calcareous and siliceous substrates as found in the European Alps. When closely related species with contrasting substrate preferences are found in the same area, it is generally hypothesized that they diverged where they now occur. However, it is possible that Alpine edaphic diversity instead allows the coexistence of related species whose edaphic differentiation took place deeper in the phylogeny, in some other part of the range of their clades.
  
  
  METHODS
  We used sequences of the nuclear internal and external transcribed spacer regions to examine the origin of substrate differentiation in Minuartia series Laricifoliae, which contains many edaphic endemics, including a pair of Alpine taxa with contrasting substrate preferences: Minuartia langii (calcicole) and M. laricifolia (calcifuge).
  
  
  RESULTS
  MINUARTIA LANGII and M. laricifolia are each more closely related to Balkan species than they are to each other and reached the Alps independently. The clade to which they belong is ancestrally calcicole. Minuartia langii inherited the ancestral ecology, while M. laricifolia is part of a subclade with serpentine endemics and one substrate generalist.
  
  
  CONCLUSIONS
  In the study group, taxa with contrasting substrate preferences did not diverge in the Alps. Instead, taxa whose substrate differentiation arose elsewhere, likely on the Balkan Peninsula, were preadapted to take advantage of Alpine substrate diversity.
authors.affiliation: Institut für Spezielle Botanik, Johannes Gutenberg-Universität Mainz, Bentzelweg 9a 55099 Mainz, Germany.
authors.forename: Abigail J
authors.initials: AJ
authors.lastname: Moore
authors.forename: Joachim W
authors.initials: JW
authors.lastname: Kadereit
mesh_terms: D000222:Adaptation, Physiological; D001483:Base Sequence; D044822:Biodiversity; D005075:Biological Evolution; D029748:Caryophyllaceae / Q000235:genetics*; D021901:DNA, Intergenic; D017753:Ecosystem; D005060:Europe; D049810:Genetic Speciation; D005843:Geography; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D012987:Soil; D013045:Species Specificity
chemical_list: D021901:DNA, Intergenic; D012987:Soil
keywords: Alps; Balkan Peninsula; calcicole; calcifuge; edaphic endemism; phylogenetics; serpentine