瓢甲科线粒体基因组及系统发生研究

Mitochondrial Genomes of Ladybird Beetles and Phylogenetic Implications

为了更好地理解瓢甲科的系统发生关系,我们测定了具有代表性的8种瓢虫的线粒体基因组序列,对基因组特征进行了分析,包括线粒体基因组组成、基因间隔区与重叠区、基因组排列方式和密码子使用情况等。已测得的瓤甲科昆虫线粒体长度在9 227~17 471bp,A+T含量为75.18%~80.45%。瓢甲科线粒体基因组中已知蛋白编码基因的起始密码子除cox1为AAT外,其余均为ATN,终止密码子为TAA、TAG以及不完整终止密码T。虽然瓢甲科昆虫的基因间隔区和重叠区通常较短,但也存在例外。最后我们联合了以前已经发表的12种瓢甲科线粒体基因组序列和3种扁虫总科线粒体基因(外群)构建了系统发生树,分析结果支持瓢甲科的以下关系:瓢甲科是一个单系群,瓢甲亚科、植食性瓢甲亚科也都是单系群,但红瓢虫亚科和小毛瓢虫亚科是并系群。这与前人基于形态特征的研究结果一致。此外,银叶裂臀瓢虫(Henosepilachna pusillanima)和马铃薯瓢虫(Henosepilachna vigintioctom)为姐妹群,且皆属于裂臀瓢虫属;长崎齿私虫属Afissula作为(裂臀瓢虫属Henosepilachna+豆形瓢虫属Subcuccinecla)的姐妹群,且皆属于植食性瓢甲亚科;六斑月瓢虫(Cheilomenes sexmacultoa)和十九星瓢虫(Anisosticta novemdecimpunctata)为姐妹群;六斑异瓢虫(Aiolocaria hexaspilota)和七星瓢虫(Coccinellaseptempunctata)为姐妹群;黄菌瓢虫属(Halyzia)和橙菌瓢虫属(Illeis)为姐妹群,两者同属于食菌瓢虫族;龟纹瓢虫(Propylea japonica)和方斑瓢虫(Propylaea quatuordecimpunctata)为姐妹群。

To investigate the phylogenetic relationships of the ladybird beetles, eight mitogenomes sampled from two subfamilies representing eight genera of Coccinellidae were determined in this study. Comparative analysis of mitogenomes was performed, which included genome organization, gene contents, overlapping and intergenic regions and codon usage of the protein-coding genes. The lengths of the sequenced mitogenomes of nine ladybird beetles range from 9 227~ 17 471 bp,with the A+T content of 75. 18%~80. 45%. All start codons for protein-coding genes are ATN,but for cox1 being AAT. The stop codons are TAA, TAG or the reduced T. Combined with the published coleopteran mitogenome data,we reconstructed the phylogenetic trees of Coccinellidae. The result strongly supports the following relationships : the Coccinellidae and the Epilachninae are monophyletic, while the Coccidulinae is a non-monophyletic group. Coccinellidae is supported as the sister lineage to( Endomychidae +( Discolomatidae + Lathridiidae)). At the genus or species level, the following sister group relationships are supported:(Hernosepilachna pusillanima+Henosepilachna vigintioctom),( Henosepilachna + Subcuccinella),( Cheilomenes sexmaculata +Anisosticta novemdecimpunctata),( Aiolocaria hexaspilota + Coccinella septempunctata),(Propylea japonica + Propylaea quatuordecimpunctata). In addition, Halyzia is a sister group to Illeis, both of which constitute the tribe of Psylloborini Casey.