| Hynobius maoershanensis belongs to the order Caudata. the family Hynobiidae. and the Hynobius genus. It is endemic in a very narrow area at the Mountain Maoer in Guangxi province, China. It mainly inhabits in alpine swamp at an altitude of 2000 m, the population was small and discovered in only three breeding ponds. H.maoershanensis has scientific research value. There is little molecular research about it so far since it was first found and reported in 2006. At present, the habitat’s quality of H.maoershanensis has decreased, and the quantity of its population is less. Fei et al think it will be endangered. In order to protect the resources of wild population better and provide scientific advice for H.maoershanensis’s management in the future, we use two kinds of molecular markers, microsatellite and mitochondrial D-loop, to analysis the genetic diversity of 152 H.maoershanensis’s tadpoles in four locations and provide scientific basis for its management in the future. The main results of this study are as follows:(1) We isolated 25 polymorphic microsatellite loci using 454 sequencing. Analysis of 29 Hynobius maoershanensis’s individuals showed number of alleles per locus ranged from 2 to 5, with expected (HE) and observed (HO) heterozygosity ranging from 0.034 to 0.759 and from 0.131 to 0.675, respectively.(2) The detection of genetic diversity based on microsatellite and mitochondrial D-loop showed that the genetic diversity of the H.maoershanensis’s population was at a low level. The results based on microsatellite showed that the mean number of alleles was 4.5, the mean expected heterozygosity was 0.576, the mean Polymorphism Information Content was 0.565. The results based on mitochondrial D-loop showed that the number of detected individuals was 134, the number of haplotype was 4, the haplotype polymorphism was 0.00029. Bottlenecks and genetic drift may be the factors lead to the very low genetic diversity of H.maoershanensis.(3) Genetic structure and population phylogenetic relationship based on microsatellite and mitochondrial D-loop. In the analysis based on microsatellite, we got 4 FST value from 0.012 to 0.049 (0< FST< 0.05), which showed no differentiation between sampling sites. In mitochondrial analysis,4 Fst value was from -0.0263 to 0.08703, showed little differentiation between sampling sites, sampling sites internal differences may be greater than the difference between sampling sites. Two markers displayed a rich exchange between different sampling sites, Nm value was from 4.814 to 20.869 in the analysis of microsatellite and was from 5.2452 to 33.9353 in the analysis of mitochondrial. The AMOVA analysis of the 4 sampling sites of H.maoershanensis by microsatellite and mtDNA, all indicated that the genetic differentiation of H.maoershanensis among samples was large than differentiation among sampling sites. The population of H.maoershanensis could be divided into two groups by STRUCTURE analysis that Shan ding hu population was one group and the rest three populations was another one. The two NJ trees analysis based on Microsatellite Nei genetic distance and 4 mtDNA haplotypes as same as the analysis of STRUCTURE. The results of Mantel test based on two marks showed that there was no significant correlation between the genetic differentiation among populations and the geographic distances.(5) The detection of population bottleneck effect based on microsatellite marker showed that 2 sampling sites had experienced extremely significant bottleneck effect when using 3 detection model(TPM、SMM、IAM) and MODE-SHIFT test. The M-ratio value of 4 sampling sites of H.maoershanensis were all less than the threshold 0.68, showed that the population of H.maoershanensis had experienced significant bottleneck effect in history.(6) Exploration of the dynamic history of H.maoershanensis population based on mitochondrial control region. Both the Tajima’s D values and Fu’s Fs value for the population of H.maoershanensis were less than zero and did not reach a significant level. Which showed that the population of H.maoershanensis was still in a neutral selection state, had on obvious deviation in the neutral evolution. The value of FuFs was -0.642, showed that the population of H.maoershanensis had genetic variation recently. |
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