Study On The Genetic Diversity And Genetic Structure Of Small Scale Plateau Zokor(Myospalax Baileyi)

Plateau zokor(Mospalax baileyi) is one of unqiue underground rodent species in Tibet Plateau in China, M. baileyi belongs to Genes Myosplax of Family Spalacidae and it mainly distributed in the region with 2800 m ~ 4200 m elevation. It is the typical cave-dweller animal to the environment of high altitude, low oxygen and high carbon dioxide. Mounds pushed out by the plateau zokor cover plants result in plant death, which make negative impact to rangeland ecosystem servies. However, the plateau zokor is called bioengineer in alpine meadow because it plays an important role in plant community succession, soil renewal and water conservation. Currently, the studying of genetic diversity and genetic structure for the plateau zokor is few, little is known about the dispersal characteristic and its influence factors, the genetic diversity and genetic structure of different geographic populations. This paper reported a study on plateau zokor in alpine meadow in the eastern Qilian Mountains in NW China, used microsatellite mark technology to study microsatellite loci polymorphism, population genetic diversity, gene flow exchanged among populations and genetic structure for individual assignment index and dispersal factors. The results were listed as follows:1. The microsatellite loci polymorphism of the plateau zokor. 33 alleles(Na) were found in 10 microsatellite loci of the zokors with three different populations density, the average effective alleles per locus(Ne) was 1.764, the range of and effective alleles was from 1.115(ECTI23)~2.108(ECTI5). The polymorphism information content(PIC) per locus ranged from 0.141(ECTI23) to 0.394(ECTI10), the average value was 0.312. the number of alleles was 164 in four different geographic populations, and the effective alleles was 83.6. The results implied that the polymorphism of microsatellite loci was medium level.2. The genetic diversity among four plateau zokor populations. The average effective alleles per locus of four populations(MYT, MYL, MYR, XNG) were 1.79, 1.66, 2.17, 2.75, respectively. The observed and expected heterozygosity(Ho and He) of the 10 loci were 0.32, 0.15, 0.23, 0.24 and 0.42, 0.31, 0.42, 0.50, respectively. The polymorphism information content(PIC) were 0.35, 0.21, 0.37, 0.43. The results implied that the genetic diversity of the plateau zokor was medium level.3. The genetic structure characteristics of the plateau zokor from different geographic populations. The result of Hardy-Weinberg equilibrium was significant imbalance(P < 0.01) on most locus because of inbreeding and null alleles led to less heterozygosity. The vaule of gene flow were less than 1 in four geographic populations, the gene flow between XNG and MYR was maximum(0.616), and the gene flow between MYT and MYL was minimum(0.040). The value of gene flow between MYT and other three populations was less than that of others. K = 2, Ln P(D) and delta K value were maximum, and other values were smaller. When K = 2, four populations were divided into 2 groups, MYT was a group alone, and another groups included MYL, MYR and XNG.4. The assignment index(AIc) showed that the individuals of high population density that assigned to the area with medium and low population density were 33.3%, the individuals of medium population density that assigned to the area with high and low population density were 33.3% and 22.2%, respectively. The individuals of low population density that assigned to the area with high and medium population density were 25% and 41.7%, respectively. The results showed that the movement of zokors dispersal was from high population density to low population density in the continuous linear habitats.5. The value of genetic differentiation between XNG and MYR was 0.061, which was less than the value(0.120) between XNG and MYL, the gene flow value between XNG and MYR was(0.616), more than the value(0.313) between XNG and MYL. The distance between MYL and MYR was less than 200 m isolated by river. The value of genetic differentiation between was 0.339, XNG and MYT separated by a road, which was greater than the value(0.061) between XNG and MYR. The resulted showed that the island habitat limited the gene exchange between plateau zokor populations, river and road have obvious inhibition on individuals exchange between populations and within populations.