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The Genetic Diversity And Genetic Structure Of The Midday Gerbils (Meriones Meridianus) Population In Inner Mongolia-Xinjiang Plateau

Posted on:2013-08-30Degree:MasterType:Thesis
Country:ChinaCandidate:X HuangFull Text:PDF
GTID:2230330371499307Subject:Ecology
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Midday gerbils(Meriones meridianus) are widely distributed in inner Mongolia-Xinjiang Plateau. Because of the high degree of dependence on habitat, they can be the indicator species of biodiversity in Inner Mongolia-Xinjiang Plateau for studying biogeography on this area. By using microsatellite molecular markers, we studied genetic diversity, genetic structure and did population dynamics analysis on160individuals from14samples of Midday gerbils. We tried to explain the geographical pattern of the population, combining with the geographical distance and the environment factors.In our study, we selected eight microsatellite loci, developed in the Mongolian gerbils. for utility in Midday gerbils. A total of180alleles at the8loci tested and the polymorphism information content (PIC) values0.912(0.872-0.929). F.ach locus played high polymorphism. In the fourteen populations, the average of observed heterozygosity value (HO) was0.68(0.52-0.85) and the average of expected hetergozygosity value (He) was0.79(0.71-0.85). This result showed that the high genetic diversity of the population was from the experience of long-term, severe fragmentation and geographical barrier with generated a wealth of genetic variation and evolutionary potential.Tests for differences in the distribution of allele frequencies indicated highly significant differentiation between all pairs of populations. Both the Bayesian clustering analysis of multibus genotypes and the Neighbor-joining phyligenetic tree (based on Nei’s standard genetic distance) provided clear indications of genetic divergence of all populations into three clusters. The result was the same to that from mitochondrial molecular marker technology.The AMOVA analysis revealed5.97%(Fct=0.060, P<0.001) of the variance being at among group hierarchical levels,3.83%(FST=0.041, P<0.001) of the variance being at within group hierarchical levels and90.20%(FST=0.098.P<0.001) of the total genetic variance resided within populations.Under the infinite allele model (IAM) by detecting population heterozygosity, the result showed the heterozygosity was excess (P<0.05). It suggested that midday gerbils populations experienced a bottleneck effect in the near future and the population once decreased.The Mantel test in Isolation bv Distance model showed that there were no significant correlation between genetic distance and geographical distance. It meant that the geographic distance was not the factor which hindered the movements of individuals and limited gene flow among local populations.The Distance-based multivariate analysis for a linear model analysis indicated that altitude might play the key role to affect the genetic structure of the gerbil in the plateau (P-Sequential test=0.048. based on FST matrix;P-Sequential test=0.037. based on DS matrix).
Keywords/Search Tags:Midday gerbil, Microsatellite maker, Genetic diversity, Populationgenetic structure, Genetic variation
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