Research On Identification Of Small Mammals And Parasitic Fleas By DNA Barcoding In Qinghai Province, China

The small mammals were the transmission infector of natural foci disease such as the plague, epidemic hemorrhagic fever, endemic typhus, leptospirosis, Lyme disease, tularemia and scrub typhus. The parasitical fleas can spread a variety of infectious and invasive diseases, particularly had important medical significance on study serve infectious disease such as plague.There were abundant species included more than 250 kinds of economic animals, 80 kinds of small mammals and nearly 160 species of fleas in Qinghai Province. We found five kinds of natural foci of disease (plague, brucellosis, hydatid disease, anthrax and typhus) in the above region. The spatial structure of plague natural foci was complex and diverse and character was firmed. Currently following the traditional morphological classification system it had many limitations, becausee it was not only closely related to by genetic factors, but also related to many factors of external environmental, organism developmental stages and organs and tissues differences. When plague occurred it was difficult to identify their infection source according to the animals shape and organs. So we need a molecular biology identification method to solve a pretty pass with only viscera and corrupt materials.This study is done to make clear the difference at those points. A total of 148 species were sampled representing 2 classes and 4 orders and 10 families and 31 genera. The COI gene sequences are directly through cycling sequencing method. After conbined some sequences from GenBank, we do sequence alignment using Clustal X, sequence statistics were performd using Mega 4 and phyligensis analyses under the Neighbour Joining (NJ). From these analyses we drew conclusions as follows:1. Rodents and parasitical fleas are closely distribution relation of Haidong Region in Qinghai Province, and show clear characterized in transition from the Loess to Plateau.2. By measuring COI gene sequences and analysis the genetic distance about 18 kinds of small mammals, we know the intraspecific distance=3%, interspecific distance 6-10%, intergenus distance 12-19%, intersubject more than 20%, interspecific genetic distance is significantly greater than the intraspecific genetic distance.3. By measuring COI gene sequences and analysis the genetic distance about 17 species of fleas, we know the intraspecific distance=3%, interspecific distance 5-11%, intergenus and intersubject distance 12-23%, interspecific genetic distance is significantly greater than the intraspecific genetic distance.4. NJ tree shows the same species have formed a single line with high support rate, interspecific branch is clearly and shows that mitochondrial COI gene of animal is an effective standard gene on DNA barcoding.5. In the study we find Rattus flavipectus by the molecular identification in Qinghai Province, through restrospect to the related animal records and published literature the result can fill a new provincal record.