Current genetic variation patterns across different geographic areas are mainly the result of various historical processes, including paleoclimate oscillations and tectonic events. Southern China, characterized by a complex paleoclimate and topography, presents an opportunity to examine such genetic variation patterns. Herein, we selected three species of moustache toads (Leptobrachium boringii, Leptobrachium liui and Leptobrachium leishanense) distributed across southern China to elucidate historical processes that shaped their current phylogeographic patterns based on two mitochondrial genes and eight microsatellite loci. L. boringii and L. liui are estimated to have genetically diverged from the late Miocene to the Pleistocene, which were largely associated with paleoclimate oscillations and geological barriers generated by complex mountain systems in southern China. Within L. liui, a recent split was caused by the rising of the Wuyi Mountains during the early Pleistocene. Demographic analyses revealed that complex topography might play buffering roles in Leptobrachium species during the last glacial maximum. These findings not only highlight the combined effects of climatic oscillations and tectonic events on driving genetic divergences, but also contribute to the general understanding of the phylogeography in this biodiversity hotspot.

Genes encoding the major histocompatibility complex (MHC) are excellent candidates for elucidating adaptive variation because of their essential role in immune function. Hypotheses for how genetic variations of MHC genes are maintained include balancing selection, diversifying selection and neutral events; however, which of these forces are dominant remains controversial. In this study, we determined the preliminary forces that shaped MHC geographical variation in Omei tree frog by comparing with neutral microsatellites. The results revealed high genetic diversity and significant population differentiation in MHC genes of this species. The differentiation patterns of MHC and microsatellites were uncorrelated. Stronger level of genetic differentiation in MHC genes compared with that in microsatellites (based on comparison in both genetic differentiation patterns and strength of isolation by distance patterns) indicates the effects of diversifying selection on the geographical variation of MHC genes. Considering the significant evidence of positive selection acting on antigen‐binding sites, we presumed that selection pressures may be mainly from locally different pathogens when gene flow is restricted. The results of this study contribute to a more comprehensive understanding of the evolutionary forces that maintain MHC geographical variation among natural populations.

No abstract

No abstract

Sex‐biased dispersal, which influences species’ social organization, genetic structure and evolution, is an important life‐history event. Although sex‐biased dispersal in mammals and birds has been thoroughly studied, little is known about it in amphibians. In this study, we used eight highly polymorphic microsatellite loci and two mitochondrial DNA (mtDNA) genes to infer patterns of dispersal of the Omei tree frog (Rhacophorus omeimontis). We found that the comparison between two types of markers showed higher FST values in mtDNA compared to microsatellites. Consistently, comparison of pairwise and overall FST values between the sexes revealed higher differentiation in females than in males. Furthermore, the inbreeding coefficient (FIS) and population gene diversity (HS) were lower in females than in males, whereas relatedness (r) was higher in females than in males. Females exhibited relatively higher correlation between genetic distance and geographical distance than males. Additionally, the mean assignment index (mAIC) was lower in males, whereas the variance of assignment index (vAIC) was higher in males. These evidences reflect higher genetic differentiation in females than in males, indicating male‐biased dispersal in the Omei tree frog. Considering the life history reported in this species, we discussed potential mechanisms driving the male‐biased dispersal in the Omei tree frog.