Novel gene rearrangement pattern in the mitochondrial genomes of Torleya mikhaili and Cincticostella fusca (Ephemeroptera: Ephemerellidae)

Reduviidae, a hyper-diverse family, comprise 25 subfamilies with nearly 7000 species and include many natural enemies of crop pests and vectors of human disease. To date, 75 mitochondrial genomes (mitogenomes) of assassin bugs from only 11 subfamilies have been reported. The limited sampling of mitogenome at higher categories hinders a deep understanding of mitogenome evolution and reduviid phylogeny. In this study, the first mitogenomes of Holoptilinae (Ptilocnemus lemur) and Emesinae (Ischnobaenella hainana) were sequenced. Two novel gene orders were detected in the newly sequenced mitogenomes. Combined 421 heteropteran mitogenomes, we identified 21 different gene orders and six gene rearrangement units located in three gene blocks. Comparative analyses of the diversity of gene order for each unit reveal that the tRNA gene cluster trnI-trnQ-trnM is the hotspot of heteropteran gene rearrangement. Furthermore, combined analyses of the gene rearrangement richness of each unit and the whole mitogenome among heteropteran lineages confirm Reduviidae as a ‘hot-spot group’ of gene rearrangement in Heteroptera. The phylogenetic analyses corroborate the current view of phylogenetic relationships between basal groups of Reduviidae with high support values. Our study provides deeper insights into the evolution of mitochondrial gene arrangement in Heteroptera and the early divergence of reduviids.

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Complete Mitogenome of Threespot Flounder Grammatobothus polyophthalmus (Pleuronectiformes: Bothidae) and Study on the Mechanism of Gene Rearrangement in 13 Bothids

10.21203/rs.2.9891/v1 ◽

2019 ◽

Author(s):

Hairong Luo ◽

Xiaoyu Kong ◽

Shixi Chen ◽

Wei Shi

Keyword(s):

Gene Rearrangement ◽

Structural Diversity ◽

Mitochondrial Genomes ◽

Gene Rearrangements ◽

Significant Evidence ◽

Rearrangement Process ◽

Genomic Scale ◽

Complete Mitogenome ◽

Shed Light ◽

High Diversity

Abstract Background: The mitochondrial genomes (mitogenomes) of 12 bothids (Pleuronectiformes) from eight genera have been obtained. From the data, the genomic-scale and various gene rearrangements revealed the high diversity of variation in these mitogenomes. Results: A total of 18170 bp of Grammatobothus polyophthalmus mitogenome was determined including 37 genes and two control regions (CRs). Genes encoded by L-strand were grouped to an eight-genes cluster (Q-A-C-Y-S1-ND6-E-P) except for the tRNA-N, other genes encoded by H-strand were grouped together (F-12S … CytB-T) except for the tRNA-D that was translocated to inside of the eight-genes cluster. The mitogenome of G. polyophthalmus and that of 12 known bothids possessed the similar genomic-scale rearrangements with the only differences in the various combinations of CR, tRNA-D and eight-genes cluster, and the shuffling of tRNA-V. Based on the structure character of all 13 bothid mitogenomes, the Dimer-Mitogenome and Non-Random Loss (DMNR) model was fitted to account for all these rearrangements. And the translocation of tRNA-D occurring after the DMNR process in 10 of 13 bothid mitogenomes was confirmed. The striking finding was that each of degenerated genes existing in the gene rearrangement process in 13 bothids had their counterparts of intergenic spaces. Conclusions: The result of corresponding relationship between degenerated genes and intergenic spaces provided the significant evidence to support the possibility of the DMNR model, as well as, the existing of dimeric mitogenome in mitochondrion. The findings of this study were rare phenomenona in teleost fish, which not only promoted the understanding of mitogenome structural diversity, but also shed light on studying of mitochondrial rearrangement and replication.

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