基于线粒体基因组全序列的鲟形目鱼类(Pisces:Acipenseriformes)的分子系统发育重建

MOLECULAR PHYLOGENY OF ACIPENSERIFORMES BASED ON COMPLETE MITOCHONDRIAL GENOME SEQUENCE

为厘清鲟形目鱼类的系统发育,研究新测定了中华鲟(Acipenser sinensis)、长江鲟(A. dabryanus)、短吻鲟(A. brevirostrum)、纳氏鲟(A. naccarii)、鳇(Huso dauricus)和匙吻鲟(Polyodon spathula)共6种鲟类的线粒体全基因组序列。联合已测的17种鲟类的线粒体基因组数据,利用最大似然法和贝叶斯法重建了鲟形目鱼类的分子系统发育关系,并采用似然值检验对不同的树拓扑结构进行了评价。结果表明, 6种新测鲟类的线粒体基因组大小为16521—16766 bp,编码13个蛋白质编码基因、22个转运RNA基因和2个核糖体基因,与大多数已测的鲟类的线粒体基因组结构高度相似。基于23种鲟形目鱼类线粒体基因组数据,系统发育分析的结果表明:(1)鲟形目的两个科,匙吻鲟科(Polyodontidae)和鲟科(Acipenseridae)均为单系;(2)鲟科的内部亲缘关系复杂,鲟属和鳇属的物种均不构成单系群。鲟科鱼类按分子系统发育重建结果可以分为3个类群:尖吻鲟类(A.sturio-A. oxyrinchus clade)、大西洋鲟类(Atlantic clade)和太平洋鲟类(Pacific clade)。树拓扑结构的检验结果表明,鲟科的系统发育关系为(尖吻鲟类(太平洋鲟类,大西洋鲟类))。铲鲟属(Scaphirhynchus)是大西洋鲟类的基部类群。研究也说明线粒体基因组数据在鲟形目鱼类系统与进化研究方面具有重要应用价值。

In this study,six complete mitochondrial genomes of Acipenseriforemes(Acipenser sinensis,A.dabryanus,A.brevirostrum,A.naccarii,Huso dauricus and Polyodon spathula)were successfully assembled.Based on 6 novel mitogenomes and 17 previously published mitogenomes of sturgeons and paddlefishes,the molecular phylogeny of Acipenseriformes was constructed by maximum likelihood and Bayesian method,and the tree topologies were evaluated by likelihoods value test.The results showed that the length of entire mitochondrial genomes of the six species were 16521—16766 bp,encoding 13 protein-coding genes,22 tRNA genes and two rRNA gene,which were similar to those of other sturgeons and paddlefishes.Molecular phylogenetic analyses showed that(i)the Acipenseriformes contained two monophyly families(Polyodontidae and Acipenseridae);(ii)genus Huso and Acipenser were demonstrated as nonmonophyletic and the family Acipenseridae can be divided into 3 subgroups:A.sturio-A.oxyrinchus clade,Atlantic clade and Pacific clade.Tree topology tests indicated that the phylogenetic relationship of the subfamily Acipenseridae is[A.sturio-A.oxyrinchus clade(Pacific clade,Atlantic clade)].The species of genus Scaphirhynchus has occupied the basal position of the Atlantic clade in Acipenseridae.This study showed that mitochondrial genome data has important application value in the systematic and evolutionary study of Acipenseriformes.