Effects Of Grazing On The Genetic Diversity Of Brandt 's Voles

The rodents do serious harm to our agriculture and animal husbandry production.This kind of pest occurred with certain temporal and spatial specificity.A research on the rodent population fluctuation mechanism is conducive to the prevention and control of rodents effectively.Brandt’s voles(Lasiopodomys brandtii) is one of dominant species of rodents in the northern steppe region of our country,which make serious damage to grassland vegetation,is influencing our agriculture and animal husbandry production.There are many factors to affect the grassland rodent damage,grazing is one of the main reasons of grassland rodent.As Brandt’s vole is mainly rodent on the grassland of Inner Mongolia,it is unclear if the grazing has effect on Brandt’s vole population quantity.In the meantime,it has not been reported if grazing would influence the rodent’s genetic structure.In this research,the Brandt’s vole populations of fence of moderate grazing as experimental materials in Joint Research Station of Animal Ecology in Inner Mongolia Grassland,do contrast with the Brandt’s vole populations of control fence,10 microsatellite markers were selected to study the effect of grazing on the genetic diversity of the populations.The genomic DNA was extracted by using conventional phenol/chloroform extraction method from the toe of Brandt’s vole in the fence,and the effect of genomic DNA extraction was detected by agarose gel electrophoresis and spectrophotometer;taking the extracted genomic DNA as template,with 10 of Brandt’s vole primer sequences of microsatellite markers were amplified by PCR,gene typing of each microsatellite marker loci of each individual,cloning and sequencing of the homozygous,and build the database,using POPGENE software to analyze the genetic diversity index such as number of alleles(Na),number of effective alleles(Ne) and observed heterozygosity(HO),expected heterozygosity(He),polymorphism information content(PIC) of each locus.In moderate grazing fence,the results show that the number of alleles in BVM02 、BVM03、BVM04、BVM05、BVM06、Mb13n、Mb17n、Mb28n、Mb29n、Mb31n sites respectively5,5,3,4,5,6,8,7,6,3;the number of effective alleles was respectively2.75,5.40,2.16,2.05,5.23,7.71,6.75,7.36,6.48,2.42;observed heterozygosity was respectively0.64,0.71,0.54,0.51,0.51,0.67,0.85,0.66,0.65,0.59;expected heterozygosity was respectively0.65,0.84,0.55,0.53,0.83,0.89,0.88,0.89,0.87,0.60;polymorphic information content was respectively0.48,0.60,0.47,0.47,0.50,0.54,0.64,0.66,0.63,0.52.The average number of alleles at 10 loci was 5.20, the average effective number of alleles was 4.83, the average observed heterozygosity was 0.63, the average expected heterozygosity was 0.75, and the average polymorphism information content was 0.55.In control fence, thenumber of alleles in BVM02、BVM03、BVM04、BVM05、BVM06、Mb13n、Mb17n、Mb28n、Mb29n、Mb31n sites respectively6,7,8,6,5,7,10,9,8,8;the number of effective alleles was respectively4.86,6.82,6.98,5.26,3.81,4.69,7.96,6.24,5.88,6.43;observed heterozygosity was respectively0.74,0.83,0.75,0.73,0.67,0.78,0.86,0.81,0.80,0.76;expected heterozygosity was respectively0.81,0.87,0.87,0.82,0.75,0.80,0.89,0.85,0.84,0.86;polymorphic information content was respectively0.69,0.81,0.72,0.71,0.65,0.75,0.84,0.80,0.81,0.74. The average number of alleles at 10 loci was 7.40, the average effective number of alleles was5.89, the average observed heterozygosity was 0.77, the average expected heterozygosity was 0.84, and the average polymorphism information content was0.75.The difference was significant(P<0.05), while comparing the populations’ number of the Brandt’s vole populations in the moderate grazing fence and in the control fence.And comparing the genetic diversity index between these two groups, the difference was significant(P<0.05)too.The results of this study showed as follows: grazing make the Brandt’s vole population decreased significantly, the genetic diversity of the population decreased significantly,too. All in all, grazing has some effects on the grassland quality.