BIOGEOGRAPHIC RECONSTRUCTION OF THE GENUS FERULA INFERRED FROM ANALYSES OF nrDNA AND cpDNA SEQUENCES

The divergence time of the largely Asian element, the genus Ferula L. (subtribe Ferulinae, tribe Scandiceae, Apiaceae) was initially analyzed using nrDNA, internal transcribed spacer (ITS) sequence data followed with three regions of cpDNA (rps16 and rpoC1 introns and rpoB-trnC intergenic spacers) from 141 representatives of subtribe Ferulinae (Ferula, Dorema, Leutea) and relatives. Further analyses of the biogeographical history of the Ferula group were carried out using BEAST, S-DIVA and BBM in RASP on all datasets. The results suggested that the initial split within Ferulinae occurred during Early Pliocene about 4.8 Ma and earlier ancestor of Ferula group has been originated mostly in Armeno-Iranian province. One descendent giving rises to the Ferula clade and another descendent subsequently underwent further divergence to account for Leutea lineages about 1.8-2 Ma. The rapid diversification within Ferulinae clade has occurred since the Middle Pliocene. Subsequent diversification of the Ferula clade intensified in the Irano-Turanian region during the late Pliocene in the Central Asian zone and toward west in Mediterranean zone during early Pleistocene. The ancestor of Chinese group of Ferula spread from Central Asia to eastern Asia in the Pliocene (2.2-4 Ma). The ancestor of the Mediterranean group of Ferula occurred in the West Mediterranean with high marginal probability. These diversifications likely corresponded with the Himalayas-Tibetan plateau uplift-driven climatic changes and aridification of Central Asia and also after refilling the Mediterranean basin and Zanclean flood during the Pliocene respectively.