Complete Mitochondrial Genome And Phylogenetic Analysis Of The Burmese Python(Python Bivittatus) And Genetic Differentiation Between Two Local Populations

The complete mitochondrial genome sequence of Python bivittatus （Burmese Python） was reported and analyzed in this paper. The structural features of the P. bivittatus mitochndrial genome was analyzed combined with other snake mitochondrial genome. Meanwhile, based on12kinds of protein-coding gene sequences, phylogenetic trees were constructed to explore the evolutionary status of Burmese python species. So far, there has no study on the phylogenetic analysis of the P. bivittatus by using12kinds of protein-coding genes yet. In addition, we sequenced and analyzed some control region II of P. bivittatus to research the structure and variation of control region II, and discussed the genetic diversity and genetic differentiation in populations of P. bivittatus. We hope to make a distinction between local population and Invasive population, thus providing an important scientific basis for the protection and management of P. bivittatus. The main research results were as follows:1、LA-PCR （long and accurate PCR）, nested PCR and TA-cloning methods were used to obtain the mitochondrial sequence （GenBank accession number NC₀21479）. The results showed that the mitochondrial genome of P. bivittatus was17617bp in length with13protein coding genes （COXI-III, ND1～6and ND4L、CYTB、ATP6、ATP8）,2ribosomal RNA genes（12SrRNA,16SrRNA）,22tRNA genes and duplicate control region（CRI、CRII）, which arranged in compact. But there were some differences occurred in the number of amino acids which increased or decreased comparing to other Python species. The length of the tRNA-Cys had the shortest nucleotide sequence length in22tRNAs, and no matched base pairs were found in dihydrouracil loop of tRNA-Cys.3repeat regions were found in the duplicated control regions, respectively, which might cause87-89bp differences among individuals.2、Phylogenetic relationships of snake species were constructed by using12kinds of protein-coding gene sequences, which is basically consistent with the traditional classification. The phylogenetic tree support Serpentes as a monophyletic group, which is divided into three branches:Scolecophidia, Henophidia and Caenophidia. Scolecophidia is located under the bottom of the phylogenetic tree, so it is first divided out. Henophidia is the second. To figure out the relationships of members in Pythonidae, Phylogenetic tree as inferred from partial Cyt b gene sequences were constructed by NJ method. The biogeographic characteristics of the Pythonidae is well represented in the phylogenetic tree. P. bivittatus evolved original, after the P. regius and P. molurus. P.bivittatus is closely related with P. molurus. 3、Length variations were found in control region sequences among P.bivittatus population, inculding four types of length:have0～3copies, which lies in front of Leu by70-332bp, caused by a87bp tandem repeat region.4、TA bidirectional sequencing was used to obtain part of mtDNA control region II of P. bivittatus from37Hainan individuals and28Vietnam individuals. A total of25haplotypes were sorted and the genetic diversity of P.bivittatus was not very high. ML trees and network analysis were built by the mtDNA control region, showing the two populations were divided into2clades. The fixation index （Fst） reached0.201（P<O.001）,which indicated that there were significant differences between the two populations.