基于12S rRNA基因的鹳形目系统发生关系

采用分子系统学的方法探讨鹳形目5个科之间的系统发生关系.文中测出鹳形目鸟类7种mtDNA 12SrRNA基因全序列,并结合来自Genbank的鹳形目另外7个物种及原鸡的同源区序列,经Clustal W软件对位排列后共1 009位点,包含405个变异位点,其中多态性位点381个,260个简约信息位点.基于上述序列数据,以原鸡为外群,使用距离邻接法、最大简约法、最大似然法及贝叶斯法分别重建了鹳形目5科14种的系统发生树.重建的系统发生树显示,内群中的14个种聚合为4支:鹮科构成第一支,聚在系统树的基部;锤头鹳科与鲸头鹳科聚为一支;鹭科和鹳科各自聚成一支.在比较不同建树方法的结果并进行合意树分析后认为:在鹳形目的系统发生中,鹮科可能是最早分化出的一支;锤头鹳科与鲸头鹳科之间的亲缘关系最近,它们祖先与鹭科、鹳科之间的分歧在时间上可能非常接近.鹳形目5个科之间的系统关系可以表示为:(鹮科,(鹭科,鹳科,(锤头鹳科,鲸头鹳科))).

PHYLOGENTIC RELATIONSHIPS WITHIN CICONIIFORMS BASED ON ANALYSES OF THE MITOCHONDRIAL 12S rRNA GENE

The evolutionary history of Ciconiiforms still remained controversy. Morphological,ecological studies and karyotype analysis had not draw a consensus conclusion. In present study, we tried to shed light on phylogeny of Ciconiiforms based on analysis of mtDNA 12S rRNA gene. We sequenced 12S rRNA gene of 7 Ciconiiforms species, and analyzed them together with homologous sequences of other 7 species from Genbank. The alignment of these sequences totaled 1?009 nucleotide positions,including 405 variable sites, 381 polymorphic sites and 260 parsimony informative sites. Employing Gallus gallus as outgroup, we reconstructed phylogeny of Ciconiiforms following neighbor joining method, maximum parsimony method, maximum likelihood method and Bayesian method. The species examined in this study clustered to four major clades in phylogenetic trees. Balaenicipitidae and Scopidae were clustered together first, as showed that they had the closest relationship among five families. The other three clades represented Threskiornithidae, Ardeidae and Ciconiidae respectively. The clades of Threskiornithidae was the basal one in phylogeny trees, which suggested that Threskiornithidae is the first one diverged from other families within Ciconiiforms. The clade comprised of Balaenicipitidae and Scopidae paralleled with the clades of Ardeidae and Ciconiidae, so the relationship within Ciconiiforms could be showed as(Threskiornithidae,(Ardeidae, Ciconiidae,(Scopidae, Balaenicipitidae))).