Phylogeography and post-glacial dynamics in the clonal-sexual orchid Cypripedium calceolus L.

Aim: We investigated the phylogeographic history of a clonal-sexual orchid, to test the hypothesis that current patterns of genetic diversity and differentiation retain the traces of climatic fluctuations and of the species reproductive system. Location: Europe, Siberia and Russian Far East.
Taxon: Cypripedium calceolus L. (Orchidaceae). Methods: Samples (>900, from 56 locations) were genotyped at eleven nuclear microsatellite loci and plastid sequences were obtained for a subset of them. Analysis of genetic structure and approximate Bayesian computations were performed. Species distribution modelling was used to explore the effects of past climatic fluctuations on the species range. Results: Analysis of genetic diversity reveals high heterozygosity and allele diversity, with no geographical trend. Three genetic clusters are identified with extant gene pools derived from ancestral demes in glacial refugia. Siberian populations exhibit different plastid haplotypes, supporting an earl...