Analysis Of The Genetic Diversity Of Oedaleus Asiaticus (Orthoptera:Acrididae)Populations In Inner Mongolia

Oedaleus asiaticus Bei-Bienko is one of the main pests on grassland and agro-pastoral ecotones in north China. In order to estimate genetic diversity and genetic differentiation among populations of O. asiaticus in Inner Mongolia on molecular level, this paper firstly studied preservation of specimens, extracting genome DNA from O. asiaticus specimens preserved by freezing after liquid nitrogen flash freezer, directly freezing, putting in pure ethanol and drying respectively and contrasting impacts on DNA observed among different preservations. After that,8pairs SSR primers, partial sequence of288bp ribosomes’DNA and7ISSR primers were used to analyze genetic diversity among O. asiaticus populations of15different areas in Inner Mongolia.1. Results of study on preservation of specimensUnder low temperature stress, DNA was degrading during cell death. In order to observe high quality genome DNA for Molecular Phylogenetics research, liquid nitrogen flash freezer was proposed as a more convenient and effective method for preservation of specimens, which provided guarantee for molecular biology research on Locusts.2. Results of SSR and ISSR analysis of different O. asiaticus populations1)8pairs SSR primers (Ata35, Ata52, LmIOZc67, MwGTD9, MwGTG12, MwGTC12, Ata68, Phr2T) which could provide good information for SSR analysis of genetic diversity among O. asiaticus populations with high polymorphism were screened based on previous researchers. Average allele number amplified from15O. asiaticus geographical populations by8pairs SSR primer was8.8750, the average efficient allelic number was7.3312and average genetic polymorphism number was0.5601, indicating the8sites were all polymorphism sites and could provide sufficient information for genetic diversity analysis.2)7suitable ISSR primers (807,810,811,812,823,880,899) with bright, legible amplification bands and good repeatability were screened from100universal ISSR primers designed and published by Columbia University in Canada for O. asiaticus populations.7ISSR primers amplified85bright and legible bands. Each primer amplified9～15bands and the average number was12.1429. Every band was polymorphism band. Average genetic polymorphism number of7ISSR primers was0.8466and bigger than0.5. The results indicated that7ISSR primers could provide sufficient information for this research.3)15Oedaleus asiaticus populations had intermediate-level gene exchange (1<Nm<4), big genetic diversity and differentiation. Results of mantel testing of15populations indicated that there was extreme significant relationship between genetic distance and geographic distance. Geographical obstructions such as geographic distance and terrain differentiation were suggested to be main factors for limiting gene communication among populations and generating high genetic differentiation.3. Results of analysis on partial sequence of ribosomes’DNA1) G+C contents was higher than A+T contents in Oedaleus asiaticus288bp ribosomes’DNA sequence. Base compositions were different among different species and differentation also existed in one species, contrasting to previous researches.2) As rDNA sequence contained less information and could not reflect all laws of genetic diversity. It was not suitable for research on genetic differentation under Locust species level, which was consistent with previous researches.