The Mitochondrial Genomes Of Ampittia Dioscorides And Papilio Polytes And Phylogenetic Analysis Of Butterflies

Butterflies belong to the Insecta, Lepidoptera. Up to now,they are used as the important model organism for the studies of evolution, population genetics, developmental biology, conservation biology, ecology, and so on. The taxonomic status and the phylogenetic position of Hesperiidae within Lepidoptera remain a controversial issue.The complete mitochondrial genome of Ampittia dioscorides and Papilio polytes were sequenced in this study. The phylogenetic trees were reconstructed by using the Neighbor-Joining(NJ), the Maximum parsimony method(MP) and the Bayesian Inference(BI) methods based on the nucleotide and amino acid sequence data of 13 protein coding genes (PCGs) and PCGs+wingless joint sequence.The main results are as follows:1. The genome of Ampittia dioscorides is a circular molecule 15,313 bp long. It contain 13 protein-coding genes,22 tRNA genes,2 rRNA genes and A+T-rich region. The gene arrangements and transcribing directions were identical to most of the reported Lepidoptera mitogenomes. The base composition of the whole genome and genes or regions were similar to the lepidopteran species. The nucleotide composition of the mitochondrial genome is highly A+T biased. All the protein-coding genes are initiated by typical ATN codons, except for COI begins with the CGA codon. The COII, ATP6,ND5,ND4,ND4L,CYTB and ND1 genes using ATG, the other ND2、ATP8、COⅢ and ND6 genes using ATT, and one more ND3 genes using ATA. Eight genes (ND2; ATP8, ATP6, COIII, ND5, ND4L, ND6 and Cytb) ended with a TAA stop codon, two genes (ND1 and ND3) with TAG. The remaining three genes (COI and COII with TA-, ND4 with T-) had incomplete stop codons. All tRNAs have a typical clover-leaf structure of mitochondrial tRNAs, except for tRNASer(AGY). The 389 bp long A+T-rich region harbored 19 bp long tandem repeats sequences and the transcription and replication origin for both strands.2.The genome of Papilio polytes is a circular molecule 15,260 bp long. It contain 13 protein-coding genes,22 tRNA genes,2 rRNA genes and A+T-rich region. The gene arrangements and transcribing directions were identical to most of the reported Lepidoptera mitogenomes. The base composition of the whole genome and genes or regions were similar to the lepidopteran species. All the protein-coding genes are initiated by typical ATN codons, except for COI begins with the CGA codon. The COII, ATP6,ND4 and ND1 genes using ATG, the other ND2,ATP8,COIII and ND3 genes using ATT, and ND5,ND4L,ND6 and Cytb genes using ATA. Seven genes (ATP8,ATP6,ND3,ND5,ND4L,ND6 and Cytb) ended with a TAA stop codon, one genes (ND1) with TAG. The remaining five genes (ND2,COI,COII,COIII and ND4 with T-) had incomplete stop codons. All tRNAs have a typical clover-leaf structure of mitochondrial tRNAs, except for tRNASer(AGY). The 439 bp long A+T-rich region harbored 10 bp long tandem repeats sequences and the transcription and replication origin for both strands.3.Based on nucleotide and amino acid sequence of 13 protein coding genes (PCGs) and PCGs+wingless joint sequence of 22 kinds of butterflies, the NJ and MP and BI trees were constructed respectively. And the twelve phylogenetic trees have similar topologies that Nymphalidae is at the top of the phylogenetic trees, Papilionidae or Hesperiidae is located in the base of the trees, and Pieridae is above the Papilionidae. However, the positional relationships between Papilionidae and Hesperiidae, Lycaenidae and Pieridae were not stable enough. In the phylogenetic trees, six families of butterflies are presented as monophyly. In addition, Danaidae and Nymphalidae have close genetic relationship to support the Danaidae as a family level taxa taxon view.