从细胞色素b基因序列变异分析中国鲇形目鱼类的系统发育

采用PCR技术获得中国鲇形目鱼类11科24属27个代表种类细胞色素b基因1138bp全序列，比较分析了来自北美洲、非洲的部分鲇形目鱼类同一基因序列，并选取脂鲤目、鲤形目和鲱形目鱼类作外类群，采用Bayesian方法和最大简约法(MP)构建分子系统树。结果表明：(1)鲇形目鱼类细胞色素b基因序列中，与脂鲤目、鲤形目以及鲱形目鱼类相比存在3bp的缺失；(2)鲇形目鱼类各科代表种类形成一单系群；(3)两种建树方法均支持铫科、粒鲇科和钝头鮠科形成一单系群；而胡子鲇科、刀鲇科、海鲇科、鮰科、长臀鮠科、鲢科、鲇科、棘脂鲿科、鲿科形成一大的单系群；但鳗鲇科的系统位置两种建树方法没有取得一致结果；而其中长臀鲍科与北美的鮰科形成姐妹群，胡子鲇、鮰科、鲇科、鲿科和鮡科是较明显的单系群。

Phylogeny of Chinese Catfishes Inferred from Mitochondrial Cytochrome b Sequences

The mitochondrial DNA cytochrome b gene was sequenced from 27 catfish species representing 11 families and 24 genera catfishes in China.Aligning with cytochrome b sequences of eight catfish species from North America and Africa retrieved from GenBank,and selecting Astyanax mexicanu,Cyprinus carpio,and Sardinops melanostictus as outgroups,we constructed a matrix of 38 DNA sequences.The phylogenetic trees were constructed by using Bayesian method and Maximum Parsimony (MP) method.The results showed that (1) there are three base pair deletions of mitochondrial cytochrome b gene compared with Characiformes,Cypriniformes,and Clupeiformes; (2) the representatives of Chinese catfish species form a monophyletic group; and (3) the molecular phylogenetic trees constructed with both methods suggest that the families Sisoridae,Akysidae and Amblycipitidae form a monophyletic group,and the families Clariidae,Schilbidae,Ariidae,Ictaluridae,Cranoglanididae,Pangasiidae,Siluridae,Claroteidae,and Bagridae also form a monophyletic group.The families Cranoglanididae from China and Ictaluridae from North America form a sister-group relationship,and the families Clariidae,Ictaluridae,Siluridae,and Sisoridae are obviously monophyletic groups.But the position of the family Plotosidae was not resolved by Bayesian analysis and maximum parsimony inference.