基于线粒体12S和16S rRNA基因部分序列的角蟾亚科部分属种的系统发育关系

Phylogenetic Relationships of Some Species and Genera in Megophryids Inferred from Partial Sequences of Mitochondrial 12S and 16S rRNA Genes

测定了角蟾亚科 2属 8种 (亚种 )和外群 3种的线粒体 12S和 16SrRNA基因部分DNA序列 ,比对后序列长共 94 9bp ,其中变异位点数 32 0 ,简约位点数 2 0 6。邻接法和最大简约法分析的系统关系树一致表明内群为一单系群 ,其中腺角蟾首先与其他物种分开 ;沙坪角蟾与宽头短腿蟾聚为一支 ;余下的 5种 (亚种 )角蟾组成一支 ,其中小角蟾短肢亚种的广西种群和香港种群聚为一亚支 ,另一亚支包括峨眉角蟾、小角蟾指名亚种、尾凸角蟾和重庆武隆的角蟾种 ,后两种角蟾进化关系最近。本结果支持短肢角蟾为有效种 ,同时提示腺角蟾、沙坪角蟾与宽头短腿蟾可能隶属 3个不同的亚属或属。

Fragments of mitochondrial 12 S and 16 S rRNA genes of 17 individuals were sequenced,including 8 species (subspecies) of 2 genera Megophrys and Brachytarsophrys of Megophrinae,and 3 species used as outgroup including the genera Bombia , Oreolalax and Scutiger .Results pairwised by Clustal W show that there are 949?bp in length with 320 variable sites including 206 parsimony sites.The average contents of T,C,A,and G are 25 6%,24 0%,29 8%,and 20 6%,respectively,and the ratio of transition to transvertion is 1 3.The phylogenetic relationships of these taxa were analyzed using programs of Neighbor Joining and Maximum Parsimony.The results show that the ingroup are clustered together as one clade,of which 3 individuals of M glandulosa were clustered together (BSP=100%) and firstly diverged from the other taxa (BSP=100%),3 individuals of B carinensis were clustered together (BSP=100%) as sister group of M shapingensis ,the rest 5 taxa formed together and included two groups,one consisting of two populations of M minor brachykolos from Longsheng of Guangxi and Hong Kong,the other containing M omeimontis,M minor minor,M caudoprocta and M sp from Wulong of Chongqing,the later two species are closely related.These results support M brachykolos as a valid species rather than a subspecies of M minor ,and suggest that M glandulosa,M shapingensis and B carinensis may belong to three different subgenera or genera.