| The mouse, Lagurus lagurus, is one of the most destructive mouse in barren-pasture land It usually stays in clay soil or barren grassland, mountainous grassland, submountain marshlands, and it is only distributed in Xinjiang, China. The present study is to analyze the population dymanics of Lagurus lagurus and compare their genetic diversities of Lagurus lagurus from Cricetulusmigratorius and Meriones meridianus .Owing to their high reproductive capacity and subjected to the factor of season, their population quantity fluctuate enormously. Furthermore, due to their habitual behavior of nibble herbage and the violent capability of digging, these greatly damage the pasture in a large scale. My investigation employed trapping and capturing of animals in the field in duration of one year for four times. The number of captured animals, (228 from September, 2000, 101 from April, 2001, 69 from July, 2001, 0 from September, 2001), were subjected into analysis of normal biology measurement, the body length, the skull and the abrasion of molar tooth, and divided into four age groups. Based on their number of foetus, we organized a static life table. The maximum rate of increase (r.) and finite rate of increase (A )of animals were calculated and sumnerized as following: 0. 6412 and 1. 8988 from September of 2000, 0. 4085 and 1. 5046 from April of 2001, 0.7607 and 2. 1398 from July of 2001, respectively. From the reproductive intensity, we can anticipate the population quantity in order to further monitor their population density, distribution and size. The observed results of population quantity from each period disagree with the anticipation value. The reason is that climate factor has dramatically impacted on expansion of Lagurus lagurus. In-virtue of the frigid of winter, aridity and torturing heat in summer, it brings the lacks of food, water and other life dependent factors, which cause the death rate increase and reproductive rate decrease resulting in the population dropped rapidly.In order to find out their genetic relationship among Microtinae,Cricetinae and Gerbillinae in Cricetidae, we have employed molecular analysis to further determine their diversity of Lagurus lagurus, Cricetulus migratorius and Merionesrneridianusand correlated their relationship in the evolutional tree. We applied forty random nucleotide primers to amplify the genomic DNA derived from those animals by polymerase chain reaction (PCR), in which established the rudimentary standardizing conditions for the random amplifying polymorphism DNA (RAPD). Among these primers, eleven primers can be used to amplify in RAPD which were accounted for 27. 5%of total primers designed. The eleven primers can amplify a range of 1 to 12 DNA fragments with those genomic DNA as templates. After the statistical analysis, we have found that the genetic distance (D) between Lagurus lagurus and Cricetulus migratorius was 0. 5844 and the genetic distance between Lagurus lagurus and Meriones weridianus was 0.7088. The relationship between Lagurus lagurus and Cricetulus migratoriu is closer than that of Lagurus lagurus with Meriones weridianus. The D value was then used to construct a dendrogram by unweighted pair-group method with arithmetical averages (UPGMA).
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