| The significant tectonic process and high degree of habitat heterogeneity has resultedin the Qinghai-Tibetan Plateau (QTP) harboring rich species endemism. Consequentlyit has been classified as a biodiversity hotspot. QTP has a high degree ofenvironmental heterogeneity including terrestrial and aquatic ecosystems whichharbors rich diversity of indigenous fauna in both terrestrial and aquatic habitats.Human disturbances and habitat degradation has significant impact on biodiversityglobally but the degree of such impact is not well studies in this region despite itssignificance as the ecological significance as the higher alpine ecosystem in the world.Basic knowledge that is important for understanding the biodiversity status andhuman impacts, such as natural history, genetic diversity and population status ofmany indigenous species is lacking. Investigate the genetic diversity and explore theadaptive evolution mechanism of the species under the stress of disturbance andenvironment changes, is essential not only for understanding the effects of globalclimate changes on natural populations but also for developing the strategies toconserve biodiversity.This study aims to investigate the genetic diversity, genetic structure and the impactof human disturbances on these aspects in terrestrial ecosystem using Gansu zokor(Mysopalacinae) as a model and aqutic ecosystem using schizothoracine fishes(Cyprinidae) as models based on microsatellite and mitochondrial control region,cytochrome b sequence analyses. We also identified the geographical distribution ofhaplotype patterns and their relationships as well as trace the postglacialrecolonizations. The main results and conclusions are listed below.1. Abundance, characteristics and exploration of microsatellite markers inGansu zokor (Eospalax cansus)Sequencing from the GS Junior System platform yielded186,832reads(82,387,680total bases) that achieved coverage of up to approximately3.1%(82.4Mb) of the genome. Among the total SSRs, the amount of dinucleotide repeats is themost abundant, accounting for60.6%of total reads, followed by tetranucleotide (16.3%), pentanucleotide (7.3%), trinucleotide (6.6%), mononucleotide (5.2%) andhexanucleotide repeats (4.0%) respectively. Our results provide baseline informationfor the screening of microsatellites, which is now underway. This will enable detailedpopulation genetic, ecology and behavioral studies to be conducted on this species and other zokor species.11were polymorphic in Gansu zokor (E. cansus) and six inthe plateau zokor (E. baileyi). These markers are the first published microsatellitesfrom E. cansus and will be invaluable for studies addressing ecological andbehavioral questions involving E. cansus and E. baileyi, and potentially other speciesin Mysopalacinae.2. Population genetic structure of Gansu zokor and their management strategiesGansu zokor has higher genetic diversity, The analysis of molecular variance(AMOVA) revealed a significant genetic structure among geographical regions.43alleles on10loci were detected in total, the average observed heterozygosity was0.443, the average expected heterozygosity was0.523, and the average polymorphicinformation content (PIC) was0.452. And genetic differentiation between populationsand rare alleles, allele frequency differences were detected even in adjacentpopulations. Gene flow between populations was8.24. Further studies are also neededto explore the adaptive evolution mechanism of the species under the stress ofdisturbance and agricultural and livestock production environment changes. And thusprovide theoretical evidence for guidance rodent infestation monitoring and integratedmanagement strategies.3. Population genetic structure of three schizothoracine fishes and their manage-ment strategiesWe found that all five Platypharodon extremus populations displayed lownucleotide diversity suggesting severe historical bottleneck events and high haplotypediversity indicating recent population expansion. Both the phylogenetic tree and theminimum spanning tree showed no significant genealogical structures correspondingto sampling locations. Population histories including bottleneck, exponentialexpansion and the absence of population structure indicate that demographicprocesses highly influenced genetic variation within and among populations of P.extreums. The data presented is consistent with a historical bottleneck and recentpopulation expansion for all four populations based on several complementaryanalyses of the genetic data and inferred from demographic history (0.26to0.36Ma).This genetic variation and demographic processes should become the baselineinformation for evaluating genetic effects of stock enhancement program and ongoingconservation decision making.We accessed the current genetic divergence of Gymnodiptychus pachycheiluspopulation to evaluate their distributions modulated by contemporary and historicalprocesses. Population structure and demographic history were assessed by analyzing1811-base pairs of mitochondrial DNA from61individuals across a large proportion of its geographic range. Our results revealed low nucleotide diversity, suggestingsevere historical bottleneck events. Analyses of molecular variance and theconventional population statistic Fst (0.0435, P=0.0215) confirmed weak geneticstructure. The monophyly of G. pachycheilus was statistically well-supported, whiletwo divergent evolutionary clusters were identified by phylogenetic analyses,suggesting that the microgeographic population structure. The consistent scenario ofrecent population expansion of two clusters was identified based on severalcomplementary analyses of demographic history (0.096Ma and0.15Ma). Thisgenetic divergence and evolutionary process are likely to have resulted from a seriesof drainage arrangements triggered by the historical tectonic events of the region. Theresults obtained here provide a first insight in the evolutionary history and geneticstatus of this unknown fish.The control region DNA sequences of Schizopygopsis pylzovi were checked andcompared with the homologous sequences of105individuals. There was a cleargeographic clustering observed in the haplotype network corresponding to the MQpopulation, for which a phylogeographic structure also produced in the phylogeneticanalysis. The Fu’s Fs test, the distribution of pairwise differences and the networkanalysis indicate that S. pylzovi have experienced certain population expansion events,which is consistent with the hypothesis that the headwater area of the Yellow Riverwas dramatically affected by the geological and climatic upheaval during thePleistocene. Analysis of molecular variance (AMOVA) showed that98.78%,indicating weak genetic structure among the five populations. Our analysis indicatedthe MU corresponding to the MQ S. pylzovi population should be managed andconserved firstly. We suggest that all the five S. pylzovi populations should bemanaged and conserved as a whole. In situ conservation is recommended as priorityfor conserving this species, for which it is important to protect its original habitatsfrom further destruction.The results obtained here are useful to determine the evolutionary process of thoseanimal populations, which will provide the important baseline information forunderstanding the population genetics, dynamic and human impact for both terrestrialand aquatic ecosystems and for developing conservation and management strategies. |
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