The Effect Of The Quaternary Glacial Climate On The Phylogeny Of Chinese Myotis And The Genetic Structure Of Rhinolophus Pusillus

The temperature was varied during the Quaternary, which consisted of an alternating sequence of multiple glacial and interglacial periods. The glacial climate has an important effet on the animals’phylogeny and population genetic structure. The climatic condition during the Quaternary brought China considerable geographical changes, which effected the animals’distribution and dispersal. The existence of the glaciation and/or refuge in Eastern China remains uncertain. In this study, we have combined the mitochondrial DNA (mtDNA) control region and cyochrome b (Cyt b) gene sequences to investigate the phylogenetic biogeography of 23 specimens of 19 Myotis on the level of genus, and also used the control region hypervariable damain (HV I) to analysis the molecular phylogeography of 23 Rhinolophus pusillus Chinese populations with 128 individuals on the level of species. The researches on the both genus and species levels are got together to presume the climate environment in the Quaternary, and its effect on the species evolution and population distribution.The Cyt b-based phylogenetic result of the Myotis has showed clear phylogenetic status of these Chinese Myotis species, which are not reflected by the current morphology-based subdivision. All of the 5 daubentonii group species are divergent from each other, indicating that the morphological and behavioral resemblances in this group are caused by convergent evolution. Myotis alatrium forms a monophyletic group with two allopatric species M. ikonnikovi and M. mystacinus, suggesting that their morphological differences might have been caused by their eco-enviornment differences.With the exception of M. sp2, species in Clade III such as M. siligorensis, M. davidii, M. longipes, and M. sp1 have been separated from each other about 2.8 Mya. Clade III with recent and low-level divergence, and high-level biodiversity, may be interrupted by the glacial climate. The phylogencies based on the control region, Cyt b gene, and both of them show 3 different relationships. The evolution patterns of the two genes show some differences in the species with low-level divergence. The noncoding control region gene gives more responses to environment changes in the evolution process.The control region of Chinese Myotis can be divided into ETAS, CD and CSB domains. RS1 and RS2 repeat sequences located in the ETAS and CSB damain separately. The length of the control region with only one repeat unit in each RS region is 968-1157 bp. The segment with most length heterogeneity is in the ETAS domain, especially the sequences between tRNA-Pro and ETAS1 element (38-203 bp). The conserved elements generally existed in mammals such as ETAS1, ETAS2, F, E, D, C, B, CSB1, CSB2 and CSB3 have been detected. An ETAS1-like element has been detected in M. ricketti, a CSB1-like element has been detected in every Myotis, and a partial repeat of the the CSB1-like sequence has been detected in M. macrodactylus.The RS1 repeat sequence in the ETAS domain of Myotis has a length of about 81 bp. The First repeats with classical beginning show some similarity among different individuals, but more variation between repeat units within the same specimens. The 70th, 75th, and 80th positions show very high similarities among different individuals. The secondary structures of the First, Middle, and Last repeat, as well as the variation frequencies of the repeat unit, suggest that the beginning of the repeat sequences should be moved toward the 5′end for 17 bp.The extraordinary high haplotype diversity and the nucleotide diversity suggest that all of the Rhinolophus pusillus in mainland China is a metapopulation including a lot of local populations. A high level of genentic diversity is observed in Eastern populations, some of which are observed non-significient or low-level divergence, implying that a colony with frequent gene flow locates in this area. The eastern populations gather into Clade A in the haplotype phylogeny, and split off about 74000 years ago, which is in the interglacial period. Then the genetic diversity has decreased when the glacial period came. At the late glacial period about 18000 years ago, the eastern populations started to expand to the center and western China. The populations in the center and western China consist of two lineages, one of which is the local individuals, and the other is from the eastern China.During the Quaternary, the evolution of the Myotis species in Clade III has been interrupted by the variation of the climate condition, which is expressed by different phylogenetic relationships based on different gene marker. The colonization history of the R. pusillus populations in eastern China also shows a response to the glacial climate. Both of the results suggest the climatic variation in eastern China during the Quaternary glacial period. At the same time, the species in Clade III were keeping evolution and generated high diverisity; the eastern populations of the R. pusillus survived and performed an expansion later. And these evidences indicate the existence of the refuge which is suitable for the species to survive and evolve during the glacial period.