| This dissertation deals with the phylogenetic relationships among some important phytoseiidae mites based on ITS and the genetic diversity of phytoseiidae populations was evaluated by using ISSR molecular marker. Moreover, the genetic structure and group diffence were also analyzed and discussed. The paper mainly involves the following two aspects.1 Molecular phylogenetic analysis of phytoseiidae mitesBased on comparative analysis of the 17 phytoseiidae mites ITS sequences (including the four experiment measured phytoseiid mites ITS sequences and obtained ITS sequences of 13 phytoseiidae mites from Genbank) and understanding of the phylogenetic relationships among species.Experiment data for four phytoseiidae mites ITS fragments,the content of A+T was 57.63%, G+C was 42.38%. In the ITS1,5.8S and ITS2 of three sections, ITS1 section contains 117 variable sites and 20 parsimony informative sites. ITS2 section contains 16 variable sites and parsimony informative sites were 2.5.8S section of the variable sites and parsimony informative sites were 8 and 1. In ITS fragments of 17 phytoseiidae mites, the content of A+T was 57.5% and G+C was 42.5%. ITS1 section contains 214 variable sites,137 parsimony informative sites. ITS2 section contains 44 variable sites and 12 parsimony informative sites. Relative to these two sections,5.8S sections of variable sites and parsimony informative sites were 19 and 4. Insertion /deletion sections focused on ITS1 and ITS2.5.8S sequences of insertions/deletions was relatively small.5.8S section showed very high conservative. M.occidentalis had the most transitions/transversions and T.pyri had the most insertions/deletions sections.Through the ITS phylogenetic trees show that Neoseiulus and Phytoseiulus had close relationship,Iphiseius and Euseius had close relationship. MP and NJ trees were shown Galendromus as a separate branch was diatant genetic relationship with the others.A. tsugawai and A.alpinus were classified to the branch of more Neoseiulus, and A. herbicolus was classified to the branch of more Euseius. Construction of ITS gene sequences based on the molecular tree showed the relationship was{[(Neoseiulus+some Amblyseius)+Phytoseiulus]+[(Euseius+some Amblyseius)+Iphiseius)]+Typhlodromus}+Galendromus.In this study 17 phytoseiidae mites were the same family in different genera, using ITS sequences can better build their molecular phylogenetic tree, to understand their genetic relationships. It also shows that ITS gene can solve the phytoseiidae mite species of the genus between the low-order element phylogeny.2 Analysis to genetic diversity of N. barkeri populations(1) Optimization of ISSR-PCR reaction system:the optimal amplification system was established with orthogonal design.2.5μL 10×PCR buffer,1.5μL MgCl2, 0.20μL Taq DNA polymerase,0.625μL dNTPs,0.25μL primers,4μL template DNA and 15.925μL ddH2O.(2) Amplification results:thirteen primers had been selected to amplify the genome DNA of 3 sampled populations (AY, DY and XF). Total 52 bands were yielded,22 of which were polymorphic bands. The percentage of polymorphic bands (PPB) was 42.31%.(3) Analysis to genetic diversity:the evaluation of population genetic diversity, which was executed by the percentage of polymorphic bands (PPB), Shannon information index (I) and expected heterozygosity (He) respectively, provided the same conclusion that the levels of the genetic diversity could be ordered in abundance as AY>DY=XF.(4) Genetic structure and gene flow:Gst was 0.6810, indicating a high level of genetic differentiation within populations.Dendrogram constructed using the UPMGA method and Nei's unbias genetic distance displayed the relationships between the 3 sampled populations:it has almost no difference between DY and XF., while AY is far and above the two populations distant genetic relationship, but not much difference. |
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