Genetic Diversity In Populations Of Tyrophagus Putrescentiae(Schrank) Revealed By Inter Simple Sequence Repeats (ISSR)

Inter simple sequence repeats(ISSR) polymorphism was used to examine thegenetic structure and genetic diversity of Tyrophagus putrescentiae(Schrank), inJiangxi Province China. for the first time in our research.(1)The research analyse the optimum project of extracting DNA of.T. putrescentiae: number of the mites was 100; The reaction system (250μL):SDS(10%)40μL,proteinase K(10mg/mL)10μL,STE 200μL; The temperature ofdigesting was 45℃.(2)The research optimized the reaction system of ISSR-PCR. The optimalreaction system: (25μL)Buffer 2.5 mM; Mg²⁺ 1.5 mM; dNTPs 0.2 mM; ISSR primers0.2μM; DNA 20 ng; Taq DNA polymerase 0.75U.(3)Forty ISSR primers were screened and 12 primers were selected for theirability to produce clear and reproducible patterns of multiple bands. The primerswere used for analysing the genetic diversity of the populations of T. putrescentiae.collected in feedstuff and mushroom in Nanchang, Ganzhou, Jiujiang city, in JiangxiProvince China (GZ-S, JJ-S, NC-S, NC-J). A total of 121 DNA bands wereamplified, 84 of which were polymophic and the percent of polymorphic bands(PPB)was 69.42%. A relatively high level of intraspecific genetic diversity was revealed:He=0.1576, I=0.2259 and PPB=36.57% at population level; He=0.2839, I=0.4118and PPB=69.42% at species level. This study demonstrated that the level of geneticvariation of the Jiujiang population(JJ-S)(H=0.2175; I=0.3127; PPB=51.24%) washigher than that of the other populations.(4)Genetic distance UPGMA system occurrence tree clustering result display,Genetic distance (SD) between populations ranged from 0.1005 to 0.1810, with anaverage of 0.1435±0.0277, and Genetic identity (SD) between populations rangedfrom 0.8344 to 0.9044, with average is 0.8666±0.0251. Nei's genetic diversityanalysis showed a low frequency of gene flow (Gst=0.3496; Nm=0.9302) existed.Analysis indicated that there was a certain genetic differentiation between thesepopulations, The relationship between two Nanchang population is closest; relationship between Jiujiang population and other population is farthest. Looked from the experimentalresult that, the geographical isolation influence to genetic differentiation is stronger than thehost factor influence.