Resistance, emigration, or adaptation? Phylogeography and ecology of European alpine plant species
Zetzsche, Holger , Blattner, Frank R. .
Phylogeography and character evolution of the radiating Pulsatilla alpina species complex (Ranunculaceae).
The showy Mountain Pasqueflowers Pulsatilla alpina, P. aurea, and P. occidentalis from Eurasian and western North American alpine pastures form a molecular and morphological well defined species complex within Pulsatilla. The evolutionary history of this group was reconstructed based upon sequence analysis of the chloroplast spacer trnL-F and the nuclear rDNA ITS region of altogether 367 individuals from 67 populations. Neighbor-joining, maximum parsimony, nested clade analysis, and Fst statistics revealed the phylogenetic relationships, ancient dipersal events and a pronounced genetical structuring among the populations.
Our data supports the origin of the whole species complex in Asia and the migration from Asia to European mountain ranges and to North America. The phylogenetic separation of the New World P. occidentalis from the other species started 5 million years ago (mya). Pulsatilla alpina split from P. aurea approximately 1.8 mya. The radiation of P. alpina in Europe took place in the Pleistocene starting about 1.4 mya. Molecular data imply a possible pathway out of Asia through the southern Balkan peninsular to the southern Apennin, and an ancient European center of P. alpina within the Apennin and Corsica. The recent distribution pattern of the different geneaological lineages were caused by at least two migrational waves: (i) from the Alps to each the Pyrenees and Caucasus, and (ii) a northern dealpine spread back from the Pyrennees over the Hercynic Arc to the Tatry Mountains.
Tolerance against calcareous soils evolved once at the beginning of the European radiation. It was lost within the Alpicola-clade and the Apiifolia-clade. The yellow flower color is a derived trait that evolved two times independently. Hybridization and introgression among subspecies of P. alpina were identified to be an important recent and historic evolutionary factor.
1 - Inst. of Plant Genetics and Crop Plant Research, Dept. of Taxonomy, Corrensstr. 3, Gatersleben, D-06466, Germany
Presentation Type: Symposium
Location: Ballroom 2 (Cliff Lodge)
Date: Wednesday, August 4th, 2004
Time: 10:30 AM