Population Differentiations Of Bombina Orientalis In Northeast China

At present,the research on B.orientalis mainly focus on the evolutionary relationship and history of the population within Bombina or the distribution range of B.orientalis.Although Northeast China is the main distribution area of B.orientalis,the evolutionary relationship and history is still unclear,so it is necessary to carry out research on B.orientalis population in Northeast China.At the same time,the research on the effects of climate change and geological events on animal groups in Northeast Asia mainly focus on the Himalayan orogeny.We will reveal the Quaternary climate change and the geological events of the Tan-lu fault zone through study the population differentiation of B.orientalis in Northeast China.Filling gaps in the effects of climate changes and geological events on animal groups in Northeast Asia.B.orientalis is the only species in the Bombina which distribute in Northeast Asia.Due to its unique distribution characteristics,it is suitable to study the geological events of Northeast Asia by studying the dispersal behavior and the population genetic structure of B.orientalis.Thus,it is excellent model systems for such tasks.Our purposes is:(1)we investigate genetic diversity and structure of B.orientalis in Northeast China;(2)utilizing mitochondrial genes to reconstructe phylogenetic relationships and estimate differentiation dating;(3)sex-biased dispersal of B.orientalis;(4)we investigate the demographic history of B.orientalis;(5)using 19 bioclimatic variables to develop the species distribution of B.orientalis from the Last inter-glacial to 2070.The major results were as follow:(1)The result of genetic structure shows that there is significant population differentiation in the northern Tan-Lu fault zone,which covering HHS,HHC,HHX and HHM form an isolated population(population I)and HHW,HMW,HMS,HMM,HD,JBL,JL,JTY and LDK form an original population(population II).(2)Based on the analysis of mt DNA,haplotype diversity(Hd)is 0.774,nucleotide diversity(?)is 0.00182.The level of genetic diversity of population ? is significantly higher than that of population ?(population ?: Hd: 0.443,?: 0.00035;population ?: Hd: 0.869,?: 0.00226).Based on the SSR data,observed heterozygosity(Ho)is 0.479,expected heterozygosity(He)is 0.540.Compare with population ?,population ? also shows a higher level of genetic diversity(population ?: Ho: 0.389,He: 0.431;Population ?: Ho: 0.519,He: 0.558).Based on the SNP data,Ho is 0.303,He is 0.313.Compare with population ?,population ? also shows a higher level of genetic diversity(population ?: Ho: 0.282,He: 0.270;Population ?: Ho: 324,He: 0.325).(3)Studies have shown that B.orientalis have a sex-biased dispersal and can experience long-distance dispersal(>30 km).(4)The differentiation dating of B.orientalis in Northeast China is 0.24 Mya.Clade ? containing all of our sampling sites with the exception of HD and QS differentiate from 0.18 Mya,at the same time,the sub-clade containing population I differentiate from 0.11 Mya.Clade ? containing all sampling sites except HHS,HHC,HHX,HHM,HMW and JL differentiate from 0.17 Mya.(5)The demographic history shows that the mismatch distribution of population ? exhibit Lshaped which indicate populations stabilize which was consistent with the result of BSP.The shape of the mismatch distribution of population ? shows bimodal,so population ? has not experienced expansions,combined with the result of BSP,the population has not experienced expansion,but the population size has declined in recent years.The results of the mismatch distribution shows that B.orientalis in Northeast China exhibit unimodal,indicate that demographic history of population has experienced expansions,combine with the result of BSP,population is steady and then the population have experienced expansion.(6)The results of species distribution show that the suitable habitat of B.orientalis in the Last inter-glacial mainly concentrate in Northeast China and the Korean Peninsula.During Last Glacial Maximum,the suitable habitat move southward.Northeast China is not a suitable habitat at this time.In Mid Holocene,the temperature gradually warmed up,and the suitable habitat gradually move northward.At this time,Northeast China once again became a suitable habitat,and the suitable habitat of the Mid Holocene is almost the same as the present.In the future,the suitable habitat gradually moves northward,and Northeast China becomes the optimal habitat.The differentiation mechanism of B.orientalis is a typical dispersal-isolation evolution model.That is,it expands the distribution range through dispersal during the specific Quaternary interglacial period,and the geological events lead to population isolation.The results of population differentiation dating show that population I differentiate from 0.11 Mya,combine with the results of species distribution modeling,Northeast China is a suitable habitat for B.orientalis.The differentiation of B.orientalis population is caused by geological events at first.The Yilan-Yitong fault zone had a strong activity in the late Pleistocene,resulting in the geographical isolation of B.orientalis population in Northeast China.For a long time later,due to the strong activity of the fault zone and the arrival of the glacial period,population of B.orientalis began to differentiation.