Molecular Phylogenetics Analysis Of Psoroptidae Isolates Based On COI, 18SrRNA Genes

Psoroptic acariasis is a infectious,stubborn,chronic dermatosis caused by psoroptidae mites,which can cause the decrease of quality and quantity in animal production,and even lead death.Accurately identification of mites is the basis of biology,immunology and prevention of this disease.With the highly development of molecular biology,the molecular systematization has been used in all areas of species classified as a branch,included in parasitic species taxonomy.In this paper,cytochrome coxidase subunit I(COI) and ribosomal 18SrRNA gene as targets were used to analyse phylogentic relation about 7 psoroptidae isolates.Sequence alignments were used to analyse the difference of sequences by DNAStar and Clustal X program.Different evolutional approaches include Unweighted pair group with mathematical average(UPGMA),neighbourjoiner (NJ) and maximum parsimony(MP),from distance matrix and character state, were used to construct the phylogenetic tree by MEGA 2.1 program.The result of sequences alignment and phylogenetic tree were used to evaluate the evolutional relation among psoroptidaes.This study successfully amplified seven psoroptidae isolates part of the COI gene sequence,the length of 633bp,632bp,632bp,630bp,631bp,632bp and 633bp. Homology analysis revealed that:Four of the chorioptes texanus from cattle had a high homology(98.9%-100%),with lower homology(87.7%-88.2%) between chorioptes panda isolate.Homology is 84.8%between psoroptes cuniculi and Psoroptes natalensis.As the same way amplified seven psoroptidae isolates part of the 18SrRNA gene sequence,the length of 915bp,918bp,918bp,917bp,918bp,918bp and 917bp Homology analysis revealed that:Four of chorioptes texanus from cattle had a high homology(99.7%～100%),with lower homology(93.2%) between chorioptes panda isolate.Homology is 97.6%between psoroptes cuniculi and Psoroptes natalensis.Based on COI and 18SrRNA sequences,phylogenetic trees(MA,NJ,ME and MP) were constructed.The results indicated that psoroptes cuniculi and Psoroptes natalensis in the same branch of the phylogenetic tree of "sister species";4 chorioptes texanus isolates from cattle always been together with chorioptes panda at the same branch of "sister species".The results indicated that psoroptes cuniculi isolate and Psoroptes natalensis isolate were different species in psoroptes,four of chorioptes texanus isolates and chorioptes panda isolate were different species in chorioptes.