Determination And Analyses Of The Mitochondrial Genome Of Odorrana Margaretae,Odorrana Huangangensis And Odorrana Graminea Using The Mitochondrial Genome Capature Sequencing

The genus Odorrana belong to Ranidae,Anura,Amphibia,and it mainly lives in swift boulder-strewn streams in the mountains of the southern China.Up to now,60 known species in Odorrrana have been identified in the world and there are 38 species in China.The odorous frogs are one of the largest genus in Ranidae,and they are mainly distributed in Southern China,the Ryukyu Islands,India northeast and Southeast Asia.In addition,it is evolutionarily significant in the history of Ranidae due to the transition from Rana to Hylorana,revealing the origin and dispersal process of this genus has been one of the key questions for evolutionary biologist.However,previous phylogenetic analyses are mainly focus on single or several molecular markers and the existence of different evolution rates among genes as well as the lack of polymorphism information sites,the taxonomy,phylogenetic relationships,species constitution and the classification of different tribes are still in controversy.In this study,we determined and analyzed the mitochondrial genomes of the type species of the genus Odorrana O.margaretae and representatives of O.schmackeri group and O.graminea group,i.e.,O.huanggang and O.graminea using the mitochondrial genome capture sequencing method.We also compared the gene order of the other five odorous frogs and explored the changes of the gene order of the mitochondrial genome in the genus Odorrana.In addition,we searched and assembled the sequences of the mitochondrial genome of representatives of Neobatrachia,different datasets were generated and phylogeny was reconstructed based on the BI and ML methods to determine the origin and phylogenetic relationships of Odorrana.The results are shown as follows:(1)The length of the mitochondrial genome of O.margaretae and O.huanggang are 17903 bp and18671 bp,respectively.Both of the mitochondrial genomes contained 37 genes and it including 13 protein coding genes,22 tRNA genes and two rRNA genes.In addition,we have sequenced 15228 bp of the mitochondrial genome for O.graminea,and it lacks the four tRNA(i.e.,tRNA-Leu,tRNA-Th,tRNA-Pro,tRNA-Phe)genes and the D-loop region.(2)The rearrangement of the gene order of the mitochondrial genome occurred in Odorrana,and all the eight odorous frogs have the same rearrangement of tRNA-His into the D-loop region.The exchange position of tRNA-Asn and Origin of L chain(O_L)occurred in O.ishikawae,O.huanggangensis and O.tianmuii,and O_L have duplicated in O.ishikawae.(3)The monophyly of the Neobatrachia,Ranidae,Dicroglossidae,Microhylidae,Rhacophoridae and Mantellidae as well as the genus Odorrana is strongly supported.Rhacophoridae and Mantellidae are sister-group relationship,and they are cluster with Ranidae,and then they formed sister-group to Dicroglossidae.In the genus Odorrana,O.margaretae clusetered with O.wuchuanensis and formed the base,O.ishikawae diversified later and clustered with the ancestral branch of O.schmackeri group and O.graminea group.However,the phylogenetic position of O.ishikawae is still unresolved due to the poor support.