Phylogeography of two closely related species of Allium endemic to East Asia: Population evolution in response to climate oscillations

Abstract

This study investigated the effects of climate oscillations on the evolution of twoclosely related Allium species, A. neriniflorum and A. tubiflorum. We sequenced threecp DNA (cpDNA) fragments (rps16, rpl32-trnL, and trnD-trnT, together approximately2,500 bp in length) of two closely related Allium species, with samples from 367 individuals in 47 populations distributed across the total range of these species. The interspecific and intraspecific divergence times of the two species were in theQuaternary glaciation. The population divergence was high for the cpDNA variation,suggesting a significant phylogeographic structure (NST = 0.844, GST = 0.798,p < 0.05). Remarkable ecological differentiation was also revealed by Niche modelsand statistical analyses. Our results suggest the speciation event of the two specieswas triggered by violent climatic changes during the Quaternary glaciation.