System Analysis Of Cheyletids (Acari: Chaeyletidae) Based On The Ribosomal 18SrRNA Gene And 28SrRNA Gene

In this paper, We successfully provide a new method which extract DNA from a single mite using Chelex-100 resin. Based on the method, we deal with the phylogenetic relationships among 4 species of 2 genera of cheyletids by using the ribosomal 18SrDNA gene and 28SrDNA gene.The cheyletids Include Cheyletus malaccensis Oudemans, Cheyletus fortis Oudemans, Cheyletus aversor Rohdendorf, Cheletomorpha lepidopterorum and Eucheyletia sinensis The main contents and results are as follows:1,Extraction of DNA from a single miteWe explore a new method which extract DNA from a single mite using Chelex-100 resin. The results show that: compared with traditional methods, this method of DNA extraction was fast and easy.Its effect was good and stable; We tested other 4 common mites, showing that Chelex-100 method could be used in all kinds of mite. Applied such small animals has many advantages:trace drawn, simple, safe and non-toxic, specimen extraction, low-cost and so on.2,Analysis of the phylogenetic relationships among four species of cheyletids 18SrDNA geneThe research of four species of cheyletids present obvious bias in base composition, the fragment has the A+T content bias. The 18SrRNA section contains 92 variable sites and parsimony informative sites were 52.The variable sites are concentrated in the middle of the fragment. Its few insertion/deletion in this section sequence.So its'relatively conservative. The genetic distance between Cheyletus malaccensis and Cheyletus fortis is 0. both compare with Cheyletus aversor in the same genus show that their genetic distance are 0.085.So we believe Cheyletus malaccensis and Cheyletus fortis are the same species.Based on the determination and analysis of the the ribosomal 18SrRNA gene sequence, molecular phylogenetic tree of four species of cheyletids (Including 3 species of Cheyletus and 1 specie of Cheletomorpha) is constructed. NJ and MP trees showed the same topology, so the phylogenetic relationships among these 7 species of Cheyletus are [(C.malaccensis+C.fortis)+Cheyletus aversor]+{ [(C.wellsi+ C.lepidopterorum)+G.sp.]+N.messersmithi)3,Analysis of the phylogenetic relationships among four species of cheyletids 28SrDNA geneThe research of four species of cheyletids present the fragments A+T and G+ C content on average flat. The 28SrRNA section contains 197 variable sites and parsimony informative sites were 72. The variable sites are concentrated in that between 100-400bp fragment. The genetic distance between Cheyletus malaccensis and Cheyletus fortis is 0. both compare with Cheyletus aversor in the same genus show that their genetic distance are 0.196.So we believe Cheyletus malaccensis and Cheyletus fortis are the same species.Based on the determination and analysis of the the ribosomal 28SrRNA gene sequence, molecular phylogenetic tree of four species of cheyletids (Including 3 species of Cheyletus and lspecie of Cheletomorpha) is constructed. NJ and MP trees showed the same topology, so the phylogenetic relationships among these 4 species of Cheyletus are [(C. malaccensis+C. fortis)+(C. aversor+C. lepidopterorum)].4,Cheyletus malaccensis populations of 18SrRNAWe Sequence five geographic populations of C.malaccensis of 18SrRNA and 28SrDNA including Nanchang, and Jiujiang of Jiangxi, Guangzhou of Guangdong Jining of Shandong, Tongcheng of Anhui.We found no differ between them. The two ribosomal genes are relatively conservative.Their are unfit for doing analysis of the cheyletids...