The Structure And Phylogenetic Evolution Of The Mitochondrial Control Region Of Gampsocleis

Mitochondria are described as "cellular power plants", because they generate most of the adenosine triphosphate (ATP) in cell. Within these subcellular organelles is a genome, separate from the nuclear chromatin, referred to as mitochondrial DNA (mtDNA). Mitochondria is the important place for cell breathing activities and produce energy. MtDNA evolves much faster (5-10 times) than single-copy nuclear (scn) DNA. MtDNA is a popular molecular marker for diverse evolutionary studies of animals, including phylogenetic inference, identification of species origin, phylogeography, analysis of population structure and dynamics, and molecular evolution. The control region (CR) is the major non-coding region of the animal mtDNA. In Hexapoda, it usually lies between srRNA and tRNAIle-tRNAGln-tRNAMet. Several structural elements have been identified in CR, such as poly-T stretch, [TA(A)]n-block, hairpin structure, flanking regions of the stem and loop, GA-block, which are believed to be involved in the regulation of transcription and the control of DNA replication.The CR has been cloned and sequenced from 56 individuals representing five species of the genus Gampsocleis, including: Gampsocleis sedakovii, G. gratiosa, G. sinensis, G. ussuriensis and G. carinata. There were 32 haplotypes in 33 individuals of G. sedakovii, 9 haplotypes in 10 individuals of G. gratiosa, 8 haplotypes in 8 individuals of G. ussuriensis, 3 haplotypes in 3 individuals of G. sinensis, 2 haplotypes in 2 individuals of G. carinata. In the CR of G. gratiosa, a 223bp sequence was found. Compared with the published insects mtDNA CR of Ensiferan, two conserved motifs“(TA)n”and“poly-A stretch”were found in the mtDNA primary sequences among twelve Ensiferan species, which may be involved in the regulation of transcription and the control of mtDNA replication.In order to verify the value of CR in molecular evolution, we constructed Neighbor-Joining (NJ) trees used the mtDNA-COI and CR sequences, under the Kimura 2-parameter (K2P) model. The result shown that the topological structures of NJ tree based on CR and COI were consistent. We found that G. sedakovii haplotypes cluster into two distinct clades A and B. The B clade mainly from the northeastern region of China, however, these two branches not corresponding in the subspecies distinction based on morphological character. According to ecotope analyses, we found the individual generally smaller and slender distributed at desert steppe region, and the individual generally larger and stouter at hilly country. We preliminarily inferred that morphological divergence between G. s. sedakovii (Mukden) and G. s. obscura (Walker) was the result of habitat dissimilarity. We approved the Northeast China (Manchuria China) was the center of G. sedakovii genetic differentiation, but disapproved of the subspecies distinction based on morphological characters. G. sinensis grouped among G. ussuriensis form clade C. The average distance within clade C was similar to that of G. sinensis or G. ussuriensis. However, the individuals of G. sinensis were only collected from Shennongjia (Hubei Province), further examination of additional G. sinensis individuals from different localities especially the type species origin was clearly needed to test the relationships between G. sinensis and G. ussuriensis. All individuals of G. carinata and G. gratiosa grouped together as sibling species in distinct clades, even collected from different localities. Therefore, the CR can be used for intraspecific genetic differentiation and phylogenetic analysis of closely species.