The Phylogenetic Relationship Of A Part Of Leiothrichidae Birds Based On MtDNA

Leiothrichidae comes from one of the families in Passeriformes,the previous Timaliidae.Among those birds in the previous Timaliidae,so called “Huamei”,the phylogenetic relationship mostly is either unknown,or controversial,so is in Leiothrichidae.In this study,LA-PCR,primer-walking and sequencing were used to get the total mtDNA sequences of B.waddelli(English name: Giant Babax),G.davidi(English name: Plain Laughingthrush),T.henrici(English name: Brown-cheeked Laughingthrush)and T.elliotii(English name: Elliot's Laughingthrush).The length of those mtDNA,the content of A,T,C and G,the protein coding genes(PCGs),the rRNA genes,the tRNA genes and the D-loop regions were analysed.Then,inorder to construct the phylogenic tree so that we could explore the phylogenic relationship among those birds and the 3 different genera,the 4 mtDNA sequences with 10 mtDNA sequences belong to Babax,Garrulax and Trochalopteron and 2 reference sequences in Leiothrix were used.Meanwhile,the tandem sequences of 13/12 PCGs from those squences,2 D-loop regions,as well as the tandem sequences of ND2,ND3 and CYTB genes from 34 birds in those 3 different genera were also used to construct the phylogenic tree.Simultaneously,we also did the reliability analysis of singlegene.The results for analysis of the 16 mtDNA sequences:(1)They were all double-stranded,covalently closed circular DNA molecule.The length of them was 17,615 bp ~ 17,877 bp.The content of A,T,C and G fowllows the principle of vertebrate mt,that is: C(%)>A(%)>T(%)>G(%).(2)They all contain 37 genes and D-loop region like other birds.37 genes include 13 PCGs,2 rRNA genes(12S rRNA gene and 16 S rRNA gene)and 22 tRNA genes.They all have 2 D-loop regions,the similarity of each other for different birds was 92% ~ 100%.The results after the contruction of phylogenic tree and BI and as well as ML analysis:(3)All BI and ML tree topologies of total mtDNA sequences and the tandem sequences of 13/12 PCGs were almost the same,together with trees contructed based on the tandem sequences of ND2,ND3 and CYTB genes and 2 D-loop regions.The BI tree of 2 D-loop regions was more different from others.(4)Babax birds,which splitted later than other teo genera,was located on the top of trees.Babax and Garrulax birds grouped together,we called it: the Babax—Garrulax clade.The monophyly of the 3 genera was supported in our study.Especially,all the birds in Trochalopteron grouped together with all the BI=1,ML=100,so did the two birds in Leiothrix.Two clades were each other's sister group.(5)On the tree of the tandem sequences of ND2,ND3 and CYTB genes, G.calvus was sepetraed from others in Garrulax,located on the base of the tree,related to G.striata in Grammatoptila.(6)For the reliability analysis of single-gene,the trees contructed based on each of,ATP6,16 S,ND5 and COX1 genes were more similier to those contructed based on total mtDNA sequences on topologies and branch length.Our study gave support to the previous Garrulax for being a paraphyly group and its reinterpretation: a part of the previous Garrulax species were kept,some were moved to Trochalopteron,and one species was classified into Grammatoptila.The Babax was also kept.The monophyly of both of Trochalopteron and Leiothrix was well supported.Considering the limition of species number,the ecommendation for classification of G.calvus won't give for now.