Quaternary climatic oscillations, punctuated by the Pleistocene glaciations, caused massive changes to the distribution of species in the Palaearctic realm. Recent research on the microevolution of East Asian species has focused largely on the locations of refugia during the Pleistocene glaciations and dispersal routes during the postglacial period . Much of the research has centered on tropical and subtropical species with geographic distributions that sometimes include the Palaearctic. Regardless, few detailed analyses of the populations from the Palearctic are available .

The impact of the Quaternary glaciation on eastern China’s local fauna and flora is a topic of considerable interest. Researc use mitochondrial DNA (mtDNA) sequences and coalescent simulations to test two general biogeographic hypotheses related to the effect of the Pleistocene climatic fluctuations on a widespread, eastern Chinese amphibian,Pseudepidalea raddei. Genealogical reconstructions are made and they detect major western and eastern lineages,which overlap in northwestern China, and possibly indicate the secondary contact of the populations that had entered the region from separate glacial refugia.

Coalescent tests rejected alternative hypotheses of fragmentation of either a widespread ancestor or panmixia. The tests instead supported the hypothesis of geographic isolation and a remarkable
dispersal pattern in one of the lineages. Though the Pleistocene climatic events are known to have affected the historical distributions and intra-specific divergence of Chinese squamates, coalescent and non-coalescent demographic analyses indicated that the toad P. raddei was not adversely affected by glacial cycling. Presumably, an increase in the amount of climatically mild habitats in East Asia is due to the development of monsoons since the Mid-late Pleistocene is responsible for the relatively mild effects.

Researchers from Sichuan University and Chengdu Institute of Biology, Chinese Academy of Sciences cooperated to study this job.